JUSTICES of the Supreme Court rarely announce what they are going to do before ruling. But Justice Antonin Scalia’s death two years ago has made open books of eight justices in Janus v American Federation of State, County and Municipal Employees (AFSCME), a case that could kneecap America’s labour movement. When Mr Scalia died, he and his colleagues were poised to decide whether unions could charge public workers “agency fees” even if they did not become members. The remaining justices deadlocked 4-4, leaving in place a lower-court decision that upheld the fees under Abood v Detroit Board of Education, a precedent dating from 1977.

Now Neil Gorsuch, Mr Scalia’s replacement, holds the key vote in Janus. But with a spotlight on his chair during the oral argument on February 26th, Justice Gorsuch had an apparent bout of stage fright. While his colleagues sparred over forced subsidies, free speech and the merits of Abood—which holds that mandatory fees preserve “labour peace” and prevent cheapskates from free-riding on their dues-paying colleagues—Justice Gorsuch sat mum.

“I’m not a bank,” says Mark Janus (pictured above), the Illinois social worker who brought the case. When the local AFSCME chapter draws $24 from his paycheck twice a month to help pay for collective bargaining, it advocates policies Mr Janus says he opposes. It is wrong to push for pay rises, Mr Janus says, when his state is in a “terrible financial condition” with “billions in unpaid bills”. According to Abood, it is fine to charge non-members to support collective bargaining but not to fund a union’s strictly political actions, such as campaigning. But William Messenger, Mr Janus’s lawyer, rejected that distinction. A “compulsory fee for speech to influence governmental policies” chafes against the First Amendment, too. Workers should not be obliged to support any part of a union’s mission. For Pat Hughes, president of the Liberty Justice Centre, which is supporting Mr Janus, forced fees are “un-American”.

The four liberal justices pushed back against Mr Janus’s call to overturn Abood by noting other contexts in which people finance groups or ideas they oppose without harm to their freedom of speech. University students are compelled to pay a student-activities fee, Justice Ruth Bader Ginsburg observed, though they may object on principle to campus groups receiving money. The same goes for lawyers forced to pay dues to bar associations advocating positions they reject. When Mr Messenger cited good reasons for those duties, Justice Sonia Sotomayor was incredulous: “The government purpose here is labour relations and labour peace.” Why isn’t that “a compelling state interest”?

Abandoning Abood after four decades would be a radical move for a handful of judges to foist on America, Justice Elena Kagan added. “I don’t think that we have ever overruled a case”, she said, “where reliance interests are remotely as strong as they are here.” Laws in 23 states would be upended “at once” and labour contracts would be invalidated for “maybe up to over 10m workers”. Worried about fitting a “modern framework on older cases”, Justice Stephen Breyer asked whether long-settled rulings like Abood should be dug up and analysed anew. What, he mused, about Marbury v Madison, the decision of 1803 justifying the court’s power to review the constitutionality of legislation?

With his eye on Justice Gorsuch, Justice Breyer floated what he called a “compromise”. It is possible to vindicate the rights of workers like Mr Janus without undermining the state-mandated status of public-sector unions in half of America, and the solution bears the imprimatur of solid conservative thinkers. A brief co-authored by Charles Fried, a solicitor-general under Ronald Reagan, argues that it is “manifestly incorrect” that all union speech is political. Such a view threatens to “constitutionalise every workplace dispute”. Still, Abood has grown too loose, Mr Fried writes: non-member employees should be charged only for collective bargaining, not for “lobbying, advertising and other speech outside of a state’s system for managing its workforce”. He points to an opinion from 1991 by one Justice Scalia as the model for retaining, but sharply limiting, agency fees.

Whether the junior justice, nearing his first anniversary on the court, likes this middle path will be revealed when a decision comes by the end of June. But it is clear that the jurist who usually occupies the swing seat, Anthony Kennedy, is a vote against the unions. When the lawyer for Illinois said states were keen to have a “stable, responsible, independent counter-party” on the other side of the bargaining table, Justice Kennedy erupted. Are unions the state’s “partner” in demanding higher wages, tax increases and “massive government”? For Yvonne Walker, president of California’s largest public-sector union, this was the “one-sided” rant of a man “playing Jeopardy”. He seems to “already have the answer”, she said, he’s just “phrased it in the form of a question”.