The Intelligence Authorization Act of 1996 amended the National Security Act of 1947 to permit law enforcement agencies to task the U.S. intelligence community with collecting information outside the United States about individuals who are "not United States persons." The intelligence community may collect such information "notwithstanding that the law enforcement agency intends to use the information collected for purposes of a law enforcement investigation or counterintelligence investigation."

This development blurs the traditional distinction between intelligence and law enforcement. The intersection of these two government functions raises interesting questions concerning the methods of collection, the targets of collection, and the use of the resultant information, in light of developed Fourth Amendment jurisprudence. This article examines and sorts the relevant issues to highlight potential problem areas and the applicable sources of law.

The Domestic Background of Constitutional Restraints

Since the enactment of the Bill of Rights in 1791, federal law enforcement has acted subject to constitutional restraints. The central restraint on federal investigation has been the Fourth Amendment, prohibiting unreasonable search or seizure and mandating the general requirement of a judicial warrant for either task.

At its most basic level, the Fourth Amendment has controlled federal activities within United States territory, whether directed towards American citizens, nationals, or aliens resident within the United States and its possessions. Although initially conceived as a restriction solely upon the federal government, the Fourth Amendment is one of the provisions of the Bill of Rights that has more recently come to be applied against state law enforcement as well.

Technological development in the Twentieth Century has expanded the scope of governmental law enforcement investigation. The Fourth Amendment has always covered basic physical entry and search of premises, real property and the physical person of an individual. The advent of electronic monitoring, wiretapping and surveillance gave federal law enforcement additional tools that at first raised questions of their permissibility under the Fourth Amendment.

The seminal Supreme Court case of Katz v. United States determined that electronic surveillance, specifically electronic eavesdropping or wiretapping of telephone conversations, fell under the Fourth Amendment warrant requirement. The Supreme Court set the standard for modern Fourth Amendment determinations in domestic law enforcement: The presence of a reasonable expectation of privacy by the surveillance subject in his papers, person, or possessions triggers a requirement for federal law officers to have probable cause before they may initiate the surveillance or search. The probable cause must pass independent review by a neutral and detached magistrate who will then issue a warrant for the police surveillance, specifically limiting its scope.

Congress has since then codified the procedures for federal law enforcement agencies in Title III of the Omnibus Crime Control and Safe Streets Act of 1968, found at 18 U.S.C. sees. 2510-2520 (hereinafter "Title III").

Failure to obtain a procedurally valid warrant as required by the Fourth Amendment and Katz will affect admissibility at trial of evidence against the surveillance subject. A defendant who can show violation of his Fourth amendment rights will win a motion to suppress the evidence illegally obtained and any subsequent evidence derived from that tainted information (the "fruits of the poisonous tree"). Because this remedy in practical effect can bar subsequent prosecution, considerations of admissibility and procedural validity of the search have become central to the conduct of law enforcement within the United States.

Surveillance for Intelligence Purposes

The conduct of surveillance for intelligence purposes has developed differently from that of law enforcement. Both the sources of authority to collect intelligence and the ends of that intelligence collection have given a decidedly different character to the endeavor. The legal context has accordingly differed as well.

Domestic law enforcement naturally falls within the President's authority and responsibility under the Constitution to see that the laws be faithfully executed. Among the laws that the President, and on his behalf all officers of the Executive Branch, must faithfully execute are the Fourth Amendment and Title III. The Executive therefore conducts domestic law enforcement with the contemporaneous involvement of the Congress and the judiciary, respectively, through the statutory and warrant restrictions. Because law enforcement is in its specifics first envisioned by the laws Congress enacts, executed by the President and his subordinate officers, then determined by the rulings and judgment of the Courts, it is ultimately a collaborative effort of all three branches.

In contrast, foreign intelligence has always been inseparable from the President's national security and foreign affairs powers under Article II. This is an area in which the President uniquely exercises authority with little constraint from the other branches of government. The goals of intelligence are those set by the Executive branch: What must the executive department know to better perform its functions? The ends or uses of intelligence need never leave the Executive branch; intelligence information is regularly classified, intelligence methods and sources merit protection, and executive departments should distribute the results internally only as needed. The Congress and the Courts need never enter the intelligence cycle.

The concept of exclusive Executive authority over foreign affairs has led Presidents to conduct intelligence surveillance outside of the traditional constraints of the Fourth Amendment. The President, acting through the Attorney General, approved the physical or electronic search in support of certified national defense intelligence requirements. Former federal agents have admitted to warrantless searches of diplomatic missions as well as American citizens' premises for intelligence purposes under this rationale.

While intelligence collection domestically operates today under greater safeguards and restriction, the governing regulatory regime is distinct from that of normal law enforcement. Following the Watergate era in the 1970's, unrestrained intelligence collection came under severe criticism. The opinion of the Supreme Court in United States v. United States District Court (the "Keith" case) highlighted the uneasy concerns over the threat to individual civil liberties from abuse of unmonitored executive surveillance power.

The Keith case concerned the prosecution of three defendants in the Eastern District of Michigan, before U.S. District Judge Damon J. Keith, on charges of conspiracy to destroy government property. The defendants were implicated in the dynamite bombing of a CIA office in Ann Arbor, Michigan, and the prosecution's evidence included the results of electronic surveillance (wiretaps) approved by the Attorney General "to gather intelligence information deemed necessary to protect the nation from attempts of domestic organizations to attack and subvert the existing structure of the Government." The defense challenged the constitutionality of the wiretaps under the Fourth Amendment and sought full disclosure of the defendants' overheard conversation, in preparation for a motion to suppress.

The government asserted that the surveillance was lawful as a reasonable exercise of the President's power, exercised through the Attorney General, to protect the national security. The District Court ruled for the defendant; the Court of Appeals for the Sixth Circuit affirmed. The Supreme Court in Keith affirmed the Sixth Circuit. Noting the passage of Title III following its opinion in United States v. Katz, the Court focused on Title III's advertence to the President's national security power:

Nor shall anything contained in this Chapter be deemed to limit the constitutional power of the President to take such measures as he deems necessary to protect the United States against the overthrow of the Government by force or other unlawful means, or against any other clear and present danger to the structure or existence of the Government. 48 U.S.C. s 2511(3).

The Court determined that with the quoted language, "Congress simply left presidential powers where it found them." Concluding that it was "inescapable that Congress only intended to make clear that the [Omnibus Crime Control and Safe Streets] Act simply did not legislate with respect to national security surveillances," the Court found that any Presidential authority to conduct national security surveillance without a warrant must derive from the "constitutional powers of the President."

That having been said, the Court in Keith took pains to distinguish the case before it from any instance requiring "judgment on the scope of the President's surveillance power with respect to the activities of foreign powers, within or without the country" and emphasized that it had before it "no evidence of any involvement, directly or indirectly, of a foreign power." Because the Keith case was purely one of "citizens of the United States" who had "no significant connection with a foreign power, its agents or agencies," the investigation of the defendants was essentially the same as any other criminal investigation and subject to Title III. The Court accordingly held that Fourth Amendment considerations applied, because "[t]he circumstances described do not justify complete exemption of domestic security surveillance from prior judicial scrutiny."

Yet the Court added, "[w]e emphasize before concluding this opinion, ... this case only involves the domestic aspects of national security. We have not addressed, and express no opinion as to, the issues which may be involved with respect to activities of foreign powers or their agents." As a result, the Court avoided a decision on the issues of overlap between foreign intelligence collection and domestic law enforcement investigation, whether conducted within the United States or abroad, and preserved the distinction between intelligence and law enforcement. The Keith Court acknowledged the existence of some Presidential authority in national security and foreign affairs surveillances, without delineating the extent or scope of that power. Nor had the Court addressed the admissibility of the results of any domestic or foreign surveillance; rather, it held only that the intercepted conversations should be disclosed to the defendant under the Court's prior ruling in Alderman v. United States, albeit as a preliminary step to a suppression motion.

The Foreign Intelligence Surveillance Act of 1978 ["EISA"] established the present regime governing domestic surveillance for intelligence purposes. Intelligence officers targeting agents of foreign powers within the United States must now apply for a warrant from a court created by Congress expressly for that purpose. The warrant application must show probable cause to believe that the subject is acting as an agent of a foreign power, as well as comply with requirements designed to minimize the intrusiveness of the surveillance. FISA originally contemplated only electronic surveillance; a subsequent amendment in 1994 provided for warrants approving physical searches.

FISA warrant applications are ex parte and in camera. A subject of intelligence surveillance could remain ignorant of the warrant application and its execution, or of the results. The statute relies on the probity of the Department of Justice and the members of the FISA Court to protect the interests of the FISA subject. When FISA searches lead to criminal prosecution, it is unclear whether the search results are as routinely admissible to criminal proceedings as would be those resulting from more traditional Title III warrants. The statute provides for some discovery of FISA searches after the fact. But the government retains the procedures of the Classified Information Protection Act ("CIPA') to restrict a defendant's access to intelligence methods, sources, and information.

A controversy persists as to the sufficiency of FISA procedures under the Fourth Amendment. Traditional targets of intelligence collection have infrequently been contemplated subjects of criminal law enforcement: either diplomatic immunity or broader designs of counterintelligence exploitation weigh against their prosecution. Similarly, standard law enforcement investigation from the start views its subjects as potential criminal defendants and has incentive to obtain evidence and develop a case admissible in court. But when intelligence collection under FISA leads unexpectedly to a criminal prosecution, the two regimes blend or overlap, and questions arise whether and when the investigation took on a law enforcement character and complied with the Fourth Amendment. Although publicized convictions have resulted from FISA warrants, to date each relied upon confession and plea agreement, obviating any judicial test of the FISA warrant's constitutional sufficiency.

Extraterritorial Operations

The operation of American law and law enforcement outside the United States has historically been narrow. Congress has traditionally been reluctant to exercise legislative power over conduct abroad, with notable exceptions like income taxation, antitrust and securities fraud, and general areas protective of American sovereignty and security, such as counterfeiting or espionage. The trend has changed in recent years, however, and there are now more federal crimes which specifically entail acts committed overseas.

International law has always constrained law enforcement efforts by one nation in the territory of another. Sovereignty among coequal nation states by definition excludes the enforcement authority of other sovereigns from within one's own territory. Absent the consent of the controlling sovereign, United States law enforcement authorities cannot apprehend or seize an individual without violating international law and the sovereignty of the situs nation. Individual nations further define as violations of their sovereignty and accordingly forbid other acts which they consider to be peculiarly governmental or imbued with sovereign authority, such as the taking of evidence or service of compulsory process, even in the civil, rather than criminal, judicial process.

In deference to such sovereignty concerns, cooperation between the United States and other nations in international law enforcement has historically taken place through government-to-government contacts. The United States stations Legal Attaches at many embassies, who establish liaison with host nation police forces. Formal requests for investigatory assistance pass through the Legal Attaches, or from the Department of Justice in the form of letters rogatory, to the foreign nation's police or justice agency. That nation's agencies, if they choose, will act in accordance with their own internal law, custom and procedure to obtain the investigatory information. By this means, the evidence obtained is presumptively admissible under the Fourth Amendment; federal courts will not examine the legal validity of a foreign government's acts within its own territory.

When the formal government-to-government approach is not available, whether for political or diplomatic reasons, for lack of diplomatic relations with the United States, or noncooperation on the part of the foreign nation, the United States law enforcement actor faces a stark choice. The investigation can stop there, perhaps to seek alternative routes of investigation in the United States or a third country. Or the investigation can continue in defiance of the local law.

The domestic legality of acts taken overseas, for purposes of United States courts, remains independent of any foreign government's determination. While customary international law is part of the federal common law, and treaties duly ratified are the supreme law of the land, the United States Constitution is the final authority in all federal judicial proceedings. The Fourth Amendment therefore must be considered in evaluating the validity of any law enforcement seizure, search or intelligence collection if it is to be introduced into evidence in a United States court.

With rare exception, United States courts have followed what has come to be known as the Ker-Frisbie doctrine in evaluating the seizure or arrest of a criminal defendant and its effect on the court's jurisdiction. So long as the United States court determines that it has valid subject matter jurisdiction to try the defendant of the crime charged, that court will not inquire as to how the defendant came to be brought before the court for trial. The Supreme Court's opinion in United States v. Alvarez-Machain reaffirmed this principle in declaring that the Fourth Amendment was not violated by the defendant's trial following his forcible abduction in Mexico and transport to the United States, where he was arrested and charged.

Evidence resulting from a search performed outside the United States raises questions under the Fourth Amendment, whose answers can vary with factual context. Across all situations, it is problematic to require the issuance of a United States warrant to validate a search for law enforcement purposes. No warrant issued by a United States official is presumptively valid outside the United States or its territory. To require a formal warrant would therefore seem needlessly formalistic, if not self-defeating. To attempt to enforce such a warrant abroad could offend the sovereignty of another state or violate international law.

An American citizen or national is entitled as a constituent of the American polity to the protective restrictions imposed by the Constitution upon the acts of the United States government directed towards him. The United States Government is a creation of the Constitution as the constitutive document establishing the powers given to that government by the American people, and the restrictions set upon the exercise of those powers with respect to the American people. Law enforcement could accordingly be held to requirements of reasonableness and probable cause in performing searches against United States nationals abroad.

When searches focus on aliens abroad, the legal constraint under the Constitution is the least certain. The controlling precedent concerning the Fourth Amendment's application to aliens outside the United States is United States v. Verdugo-Urquidez. Verdugo-Urquidez had been indicted on drug charges under United States law, but he was a Mexican citizen residing in Mexico. Mexican police officers delivered Verdugo-Urquidez to the United States border, where he was arrested and charged. Agents of the Drug Enforcement Administration (DEA), with the permission and assistance of the Mexican federal police, conducted searches of Verdugo-Urquidez's two houses in Mexico, obtaining documents evidencing Verdugo-Urquidez's drug smuggling.

On Verdugo-Urquidez's motion to suppress the documents, the District Court ruled the Fourth Amendment applied to the searches conducted in Mexico, and that the DEA agents had no cause to conduct those searches without a warrant. The Court of Appeals for the Ninth Circuit affirmed, ruling that the searches were subject to the Fourth Amendment, and therefore unlawful without a warrant or exigent circumstances.

In his opinion for the Supreme Court, Chief Justice Rehnquist found that the Fourth Amendment does not apply to the search and seizure of a nonresident alien's property outside of the United States. While other provisions of the Bill of Rights, such as the Fifth or Sixth Amendments, establish trial rights which inure to a person who becomes defendant in United States custody, and continue through the trial process, the Fourth Amendment is distinguishable. The Fourth Amendment's restrictions on search and seizure protect a right of "the people" as opposed to any person or any accused; a search and seizure can violate these restrictions prior to, or even absent, a trial or conviction. It therefore made no difference to a Fourth Amendment analysis, despite the dissent's protest to the contrary, whether Verdugo-Urquidez was within or without the United States, or in custody, at the time the agents searched the Mexican properties. A judicial warrant would have had null effect outside the United States. But a requirement to obtain a warrant, implied by application of the Fourth Amendment, would have a pernicious effect on United States operations overseas, including, the Court feared, military operations. The Supreme Court accordingly reversed the two lower courts' opinions.

Justice Brennan's dissenting opinion in Verdugo-Urquidez argued that despite the defendant's alienage, he was entitled to Fourth Amendment protection precisely because he was held to answer to United States law. By exercising its sovereign authority to try him under United States criminal law, the Government subjected itself to the restrictions of the Fourth Amendment.

Both the majority opinion and the dissent recognized that the Fourth Amendment applied to protect American citizens, without regard to territorial restriction. Justice Brennan sought however to base Fourth Amendment application on a principle of mutuality between investigator and investigated, with less concern for nationality or citizenship.

Justice Brennan's dissent also noted that "non-law enforcement activities, not directed against enemy aliens in wartime but nevertheless implicating national security" should not suffer impairment by his Fourth Amendment analysis. "Many situations involving sensitive operations abroad likely would involve exigent circumstances" and thus not need a warrant. Thus both the dissent and the majority in Verdugo-Urquidez leave open the possibility that intelligence collection overseas can proceed without constitutional burden, on the significant, if unstated, assumption that the intent remains unchanged throughout the investigation to collect information solely for intelligence purposes. But Justice Brennan's analysis seems necessarily to rely on the continued dichotomy between intelligence and law enforcement in distinguishing the Fourth Amendment's applicability to either function.

Considerations Applicable to Intelligence Support of Law Enforcement

The opinion and dissent in Verdugo-Urquidez set forth two competing views of the nature of the Fourth Amendment restrictions on search and seizure. Justice Brennan's dissent, dismissing distinctions of alienage and instead focusing on the fact of subjection to the criminal process, portrays the Fourth Amendment as a personal right, attaching to any individual when and as he becomes the subject of government investigation. The requirement for a warrant, in this view, is a subjective act of internal self-discipline upon the government and must therefore apply, regardless of the rest of the world's indifference to the warrant's effect, if only to keep the government honest.

The Chief Justice's opinion for the Court, on the other hand, rather than viewing the Fourth Amendment as the penitent government's hair shirt, suggests instead an objective standard that weighs the relationships between the government, the individual subject to investigation, and the conditions and circumstances attending them.

Were Justice Brennan's view to have prevailed as the Court's opinion in Verdugo-Urquidez, the present analysis of the Intelligence Authorization Act of 1996 could essentially end. The Fourth Amendment, under that view, would simply apply across the board to law enforcement activity abroad. Intelligence collection tasked toward a criminal law enforcement purpose would fall subject to the same requirement: Existing case law dictates that foreign government surveillances conducted at the behest of, or in league with, United States law enforcement officers fall within Fourth Amendment restrictions for purposes of domestic United States law. There is no reason to conclude that United States intelligence personnel activity at the behest of U.S. law enforcement agencies would not, under that view of the Fourth Amendment, fall subject to the same restrictions. The warrant requirement would be no different than in the case of an American citizen as subject, and one court at least has suggested the relevant procedure. Even were the warrant requirement to be excused, the separate requirement of reasonableness remains, and the courts would have to make a determination of reasonableness after the fact, with the intrusive evaluation of intelligence procedures and methods that would entail.

Given the actual Verdugo-Urquidez majority holding that the Fourth Amendment does not apply to nonresident aliens overseas, the analysis of intelligence support to law enforcement does not stop there. While the Constitution may not prohibit the collection of law enforcement information overseas, the Congress may yet legislate to narrow the confines of law enforcement conduct abroad. This prospect raises further questions of conflict with the Executive Branch and its inherent authority in foreign relations and national defense.

The traditional paradigm governing Presidential and Congressional powers in conflict over foreign affairs is the tripartite analysis of Justice Robert Jackson's concurring opinion in Youngstown Sheet &J Tube Co. v. Sawyer (the Steel Seizure case). Justice Jackson envisioned three possible relationships between Congressional and Presidential actions affecting the scope of Presidential power over a given topic. Where Congress has acted to grant the President discretion or authority, legislating in agreement with his role, the scope of Executive power is at its maximum. Congressional silence on an area, leaving the President's authority at the same time both unsupported and unopposed. Justice Jackson termed a "zone of twilight" in Executive authority. And, third, the President's authority is at its "lowest ebb" when he faces Congressional action directly contrary to his own, challenging his authority and leaving him solely dependent on the Constitutional powers inherent to his office.

Justice Jackson's Steel Seizure paradigm is a useful tool for examining the implications of intelligence collection in support of law enforcement. Were the Congress to enact legislation burdening, restricting, or even forbidding the tasking of intelligence collection overseas in support of law enforcement, the practice would be forced to rely on the President's Article II authority. In both the diplomatic power, as head of state, and the national security power, as Commander-in-Chief of the armed forces, the President has ample Constitutional basis to direct the law enforcement tasking, in the course of his general control of foreign intelligence collection and targeting. But the Congress may ultimately hold the trump card for law enforcement purposes, because the legislature retains authority for establishing rules of evidence and admissibility in United States courts.

When Congress, as it has for most of the nation's history, does not express any legislative view of intelligence support to law enforcement, the President retains a free hand. In Justice Jackson's "zone of twilight" absent either a Congressional grant or denial of authority, the President may proceed to task intelligence collection in support of law enforcement on his independent responsibility. But while the practice of tasking and collection may proceed, and the Executive Branch can seek to introduce the results against a defendant without Congressional disapproval, a check remains in the judgment of the federal court. Congressional silence therefore means that the President can collect law enforcement information as he were to deem prudent or necessary; but the admissibility in court would turn upon the independent assessment and weighing of the evidence by the judiciary under standard rules of evidence. In Justice Jackson's words, the situation is thus "likely to depend on the imperatives of events and contemporary imponderables rather than on abstract theories of law."

The remaining category in Justice Jackson's trilogy is the one perhaps most relevant to the present analysis, where Congress has expressly or impliedly granted authority to the President on top of his own inherent Constitutional power. Absent a Fourth Amendment warrant requirement or other Constitutional restriction, the President would be free to task intelligence collection against law enforcement targets, as well as to use the results at trial. With Congressional endorsement, the practice then falls subject only to the administrative and procedural rules imposed by the Executive Branch itself, by executive order or regulation.

For the present analysis, there is as yet no Congressional act in opposition to the exercise of intelligence collection overseas for law enforcement purposes. Prior to the enactment of the Intelligence Authorization Act of 1996, the practice existed in Justice Jackson's "zone of twilight:" Congressional silence permitted the President, if he so chose, to task intelligence collection, for law enforcement purposes, and then to use the results at trial.

The relevant portion of the text of the Intelligence Authorization Act of 1996 now brings the practice into Justice Jackson's category of maximum Presidential authority. The President presumably did not need Congressional authorization to direct the tasking of overseas intelligence collection: That would be a discretionary function essential to Presidential control of foreign affairs and intelligence. The Congressional authorization adds no new power with respect to mere information gathering, but does serve as an important clarification of the National Security Act of 1947. That Act, in creating and defining the Central Intelligence Agency, specified that the CIA was to have no police, subpoena, or arrest powers. The Intelligence Authorization Act removes any implied prohibition against CIA assistance to law enforcement and shields the Agency from charges of violating its mandate were it to give such assistance. This interpretation gains added credence from the accompanying provision delineating which components of the Department of Defense may or may not take part, suggesting deference to the traditional American sensitivity to civilian control of the military and separation of military from police power, as exemplified in the Posse Comitatus Act.

As for the admissibility of the resulting information, Congress enacted the Intelligence Authorization Act with presumed knowledge of the Supreme Court's rulings six years earlier in Verdugo-Urquidez. The statute's specification of intelligence targets who are "not United States persons" recognizes the application of the Fourth Amendment standards to surveillance of United States citizens, but not to nonresident aliens. Coupled with the approval of intelligence collection "notwithstanding that the law enforcement agency intends to use the information collected for purposes of a law enforcement investigation or counterintelligence investigation," this provision of the Act strongly suggests that the information obtained is to be admissible in a federal court despite its source or the method of its acquisition.

The statute is at the very least, then, an exhortation of the President to make use of such authority as he has in foreign intelligence to assist his law enforcement role. Even more, it evidences a Congressional intent to remove any statutory obstacle to intelligence agency cooperation with law enforcement, or to the admission into evidence by federal courts of the resulting information.

Finally, there remains one additional body of law to consider with respect to intelligence collection overseas in support of law enforcement. Where the Constitution and federal statutes are otherwise silent, international law applies as part of the federal common law. Potentially applicable international law can derive from three principal sources: bilateral treaties or agreements between the United States and individual nations; multilateral treaties or conventions to which the United States is a party; and customary international law.

Both bilateral treaties and multilateral conventions, once consented to by the Senate and ratified, have the force of federal law. In their relationship to other federal statutes, they are like any other federal enactment, and in case of conflict, the later of the two will prevail. In all cases, the Constitution takes precedence over a treaty or customary international law. International obligations of the United States entered into without a formal treaty and Senate ratification, such as executive agreements, are also internationally binding on the United States to the extent they do not conflict with the Constitution or Congressional statutes. In the event that an executive agreement conflicts with a Congressional enactment, an analysis on the order of Justice Jackson's Steel Seizure paradigm is again necessary to resolve the conflict between Presidential and Congressional authority. Courts will however construe all federal laws, to the extent at all possible, so as not to conflict with international law.

In terms of intelligence collection against law enforcement targets overseas, the Intelligence Authorization Act of 1996 is the most recent Congressional statement on the topic, and it therefore should control, in any conflict with individual bilateral treaties between the United States and other nations. Relevant agreements in this category might include extradition treaties, treaties of friendship, commerce and navigation, tax treaties, and mutual legal assistance treaties. To the extent that any of these treaties would restrict or qualify the operations of United States intelligence collection either in their countries or against their nationals, the Intelligence Authorization Act is not inconsistent, because the Act does not direct how the intelligence is to be collected. The Act merely suggests that when United States intelligence agencies operate within a given country, it is acceptable under United States domestic law to include on the target list matters of law enforcement interest, no matter what methods should be permitted. A similar analysis applies to existing multilateral treaties, which might include conventions against terrorism, conventions on the treatment of diplomatic and consular agents abroad, or conventions on the taking of evidence. Passage of the Intelligence Authorization Act does suggest that in the future, the Senate should take care in reviewing treaties submitted for its advice and consent to assess the interaction of any treaty provisions with this statute.

Any existing or future international executive agreement which addressed the issue of intelligence collection abroad for law enforcement purposes might seem to conflict with the Intelligence Authorization Act, and thereby set the executive power in opposition to the legislative. But however the President might agree, in his Constitutional authority over foreign affairs and intelligence, to set restrictions on methods of collection or operations overseas, or to refuse to submit the resulting information to the trial courts, the expressed intent of Congress under the Act remains that the courts should admit what evidence collected in that manner the prosecution should choose to offer. The perceived conflict in that situation would be a false one, because the President would merely be declining, on a case by case basis, to exercise an authority that Congress had seen fit to grant him. The President's discretion in foreign affairs and intelligence collection, as well as his prosecutorial discretion before the courts, would in turn protect him from Congressional efforts to compel him to act otherwise.

Customary international law applies to the conduct of nations only when a custom or rule among nations has become so widespread and accepted that it is not only commonly taken as law among nations but it is in fact obeyed by nations out of a sense of legal obligation (opinio juris.) The instances of customary international law are rare, and the burden is upon the party asserting that a rule is one of customary international law to prove that it has attained that status.

Much of customary international law has been codified in various modem treaties and conventions. Throughout most of history, customary international law dealt primarily with relations between States and their governments, and had very little focus on individuals or their relationships to foreign governments. The few exceptions centered on universal peremptory norms against individual conduct considered to offend all civilized nations (jus cogens), such as piracy or slavery. The governing consideration for one government's actions towards the citizens or nationals of another State was (and to a large part remains) the ability and likelihood of that alien's State of nationality to exercise its diplomatic protection on his behalf.

The post World War Two development of international human rights law has expanded the consideration by international law of how States and their governments act toward alien individuals. Longstanding customary international law has required States to treat aliens within their realm no worse than the State would treat its own nationals. International law has in modern times proclaimed certain universal and minimum standards for governments' treatment of individuals, both of their own and of alien nationality. Principal examples of these international standards are the United Nations Universal Declaration of Human Rights and the International Covenant on Civil and Political Rights.

Each of these relevant international law enactments focuses on the State's treatment of individuals found within its territorial jurisdiction. As such, they are unlikely to be much guidance for the legality of United States intelligence operations directed against individuals overseas. The more appropriate gauge of conduct in a foreign territory would remain the law of the territory's sovereign, under which an individual could be held accountable in an appropriate international forum, and derivatively, the United States might be held accountable.

In domestic prosecution of aliens by the United States on the basis of intelligence information collected overseas, the international law standards may prove relevant, although perhaps also redundant. Most if not all of the civil rights provisions of the Constitution and federal statutes applicable to criminal defendants closely follow or exceed the requirements of international standards. In those areas not addressed by the Constitution or federal statute, it is possible that over time, international standards can be received into customary international law, as, in some respects, the Universal Declaration of Human Rights has; but as yet the Declaration, among other international enactments, has no compulsory effect in United States law (despite the United States' adherence), because the Declaration is not a self-executing treaty and there is no Congressional implementing legislation to give it the force of law. Absent future developments of that nature, much of the international human rights law conventions remain at most persuasive to a federal court that might face issues of admissibility not otherwise determinable from established United States law.


Both intelligence collection overseas and law enforcement at home coexist as responsibilities of the executive branch of the federal government. Each function has in the past remained distinct of the other. Concerns of admissibility and international sovereignty limited the exercise of law enforcement overseas, while secrecy and civil rights concerns limited the use of intelligence agencies within the United States.

Because the two functions had been conceptually distinct, separate standards had developed in each area for the application of Fourth Amendment protections against search and seizure. The Fourth Amendment governs all domestic law enforcement regardless of the subject, but investigation undertaken solely for intelligence purposes met fewer prior obstacles, and the resultant information was potentially admissible against a criminal defendant despite the initial origin in an intelligence surveillance. The Fourth Amendment controls conduct directed to United States persons abroad; it protects nonresident aliens only within the United States.

With passage of the Intelligence Authorization Act of 1996, Congress has explicitly breached the conceptual separation of intelligence and law enforcement. Enlisting intelligence collection overseas in the service of domestic law enforcement blurs the distinction between the two functions and raises questions of which legal rules apply.

The current state of the law is that aliens abroad do not enjoy Fourth Amendment protection as subjects of intelligence collection tasked in support of law enforcement. The expressed intent of Congress grants the intelligence and law enforcement communities maximum Constitutional authority in this arena to pursue their legitimate ends. The President and his executive branch officers have yet to promulgate (publicly) specific orders or regulations addressing the conduct of intelligence collection abroad in support of law enforcement.

Absent the restrictions of the Fourth Amendment, and without statutory impediment, intelligence collection outside of the United States in support of law enforcement acts are subject to only two sources of legal constraint. Within the territory of another sovereign State, intelligence collection can run afoul of local municipal law; in any nation's territory (or international jurisdictions such as the high seas), the practice can fall subject to international law.

The current state of international law applicable to the subject suggests no further restrictions, other than trial forum procedural guarantees and customary standards of civilized conduct by nations toward individuals. The potential remains, however, for Congress to change this situation by statute, or, in conjunction with the President, by treaty.

*Theodore Cooperstein serves in the General Counsel's Office of the Federal Bureau of Investigation. The views expressed in this article are his alone.