On the last day of the term, the Supreme Court issued one of the most anticipated decisions of recent years, Janus v. AFSCME. As widely expected, a five-justice majority overturned Abood v. Detroit Board of Education (1977) and held that unions could not require public-sector employees to pay “agency fees” that would be used to fund the union’s collective bargaining efforts. Justice Alito, writing for the majority, explained that because “fundamental free speech rights are at stake,” the Court felt justified in abandoning Abood. The petitioner in this case, Mark Janus, objected to being required to pay his workplace union’s agency fee because he disagreed with many of its public policy positions. In siding with Janus, the Court brought an end to mandatory union fees in the public sector.

Justice Alito cited a number of factors that led the Court to find that stare decisis did not require deference to Abood. They included: criticism that Abood failed to give adequate consideration to  First Amendment concerns; difficulty determining what was an “agency fee”; and legal developments in related areas of law.

Justice Kagan wrote the dissent, which was joined by Justices Ginsburg, Breyer, and Sotomayor. She argued that Abood remains sound, and the balance it struck between union interests and public employee expression was consistent with established First Amendment doctrine. To hold otherwise, she wrote in one of the most widely quoted lines from the Janus, was nothing more than “weaponizing the First Amendment” to advance conservative interests. Justice Kagan also expressed her disagreement with the majority’s dismissive treatment of a long standing precedent. “The worst part of today’s opinion,” she wrote, “is where the majority subverts all known principles of stare decisis.”

Response to the ruling was predictably divided. Mark Janus was “ecstatic.” Conservatives praised Janus as a win for taxpayers and freedom of speech. On the other side, labor activists and unions denounced the decision and announced plans to keep fighting for union rights. Vox described Janus as the “most consequential ruling of the year”; some have estimated that teachers unions could lose up to a third of their funding. Writing in the New York Times, Jared Odessky and Miriam Frank criticized the decision as a blow to the LGBT community, who often rely on unions to advocate for their workplace rights.