From the Cato Institute's Ilya Shapiro:

The conventional wisdom is that Justice Scalia is the swing vote in Friedrichs v. California Teachers Association, but he gave no indication at this morning's argument that he was anywhere but on the plaintiffs' side. Chief Justice Roberts and Justice Kennedy -- other potential defectors from the pro-workers, anti-compelled-speech side -- were similarly solid. With Justice Alito having written the two recent labor-related opinions, the most likely fifth vote for the unions (supported by California and the United States) becomes Justice Thomas, but only because he said nothing, as is his wont. In other words, to the extent we can predict anything based solely on oral argument -- take this with a mine of salt – I’d much rather be us (those who support the teachers) than them (those who support the teachers' union and state and federal governments). If that's the case, this would be a huge victory for workers' rights, the First Amendment, and educational freedom. 

From National Right to Work attorney Bill Messenger:

Today, the United States Supreme Court considered the vital question of whether public employees can be compelled to pay dues to a union they don’t belong to or support. I believe that the plaintiffs’ arguments are both more persuasive than the respondents’ and correct as a matter of constitutional law, and I hope the High Court takes this opportunity to finally remedy the injustice of forced union dues in the public sector.

It’s gratifying to watch Rebecca Friedrichs and her co-plaintiffs build on arguments advanced by National Right to Work Foundation staff attorneys in Harris v. Quinn, a 2014 Supreme Court case that outlawed forced dues for homecare providers. Based on the Court’s rulings in Harris and Knox v. SEIU, two recent Foundation victories that touched on many of these same issues, I expect that a majority will rule against forcing civil servants to pay union dues. In the event of a favorable ruling, I and other Foundation staff attorneys will work towards ensuring the decision is enforced and public employees’ rights are respected in every workplace across the country.