Just in time for the 2016 election, the Roberts Court has found yet another way to stack the deck in favor of the rich.

By all appearances at Monday’s argument, the five Republican-appointed justices are ready to upend a 40-year precedent guiding labor relations in favor of a new approach that will deplete public-sector unions’ finances and reduce their political clout. The case, from California, involves arcane issues of “agency fees” and member opt-outs, but make no mistake: This is about campaign finance, and, in particular, propping up the Republican Party.

Citizens United and other recent rulings created the modern era of super PACs and unlimited political contributions by the wealthy. Because there are fewer liberal billionaires (and those who are politically active, such as George Soros and Tom Steyer, tend to shun super PACs in favor of their own projects) the only real counterweight to Republican super PACs in this new era is union money. And the Supreme Court is about to attack that, too.

The only question is how big a loss Friedrichs v. California Teachers Association will be for the unions. It’s virtually certain to be another step toward American oligarchy. The court’s conservative majority, setting aside a professed respect for precedent and states’ authority, is putting a thumb on the scale of justice in favor of the wealthy donors who have purchased the GOP and much of the government.

Justice Stephen Breyer, one of the Democratic appointees, argued that there were good arguments on both sides of the case, but no compelling reason to “overrule a compromise that was worked out over 40 years and has lasted reasonably well.” Said Breyer: “I guess people could overrule our decisions just as easily. And you start overruling things, what happens to the country thinking of us as a kind of stability in a world that is tough because it changes a lot?”

The answer, of course, is Americans have already come to see the court as another political branch of government. Lawyer Michael Carvin, leading the anti-union side Monday, gave further justification for that impression. In front of the justices, he dismissed the notion “that anything could happen adversely” to unions as a result of the case. But then he went out to the Supreme Court plaza and, in front of a cheering crowd, told the truth: “It may limit their revenue somewhat, but of course they can compensate for that by being less involved in things like politics.”

And that’s exactly the goal.

The huge political consequences of the case were unstated in the chamber, but the argument was at times as partisan as a debate on the House floor. Carvin frequently interrupted and talked over the three female justices — classic “mansplaining,” as Slate’s Dahlia Lithwick observed from the press seats. Carvin referred to the other side’s argument as the “so-called opposition” and pronounced Justice Sonia Sotomayor’s surname as “Soto-my-ear.” At one point he quipped that he has a First Amendment right not to join the American Bar Association, “because virtually every word out of their mouth I disagree with.” Justice Samuel Alito guffawed.

The argument was mostly for show, because there was little doubt the 1977 Abood decision will go down. This will make it easier for public-sector workers who benefit from collective bargaining but who don’t want to be in unions to avoid paying fees to the union, even for nonpolitical functions. Union finances will be further drained at a time when labor is historically weak.

Carvin spent his morning affirming the conservative justices. To Antonin Scalia: “You’re a thousand percent right, Your Honor.” To Anthony Kennedy: “Exactly, Your Honor.” To Alito: “Your recollection of history is correct.”

And these conservative justices left no doubt where they stood. Chief Justice John Roberts dismissed as “really insignificant” the unions’ argument about free riders. Scalia informed the union’s lawyer that his argument “doesn’t mean anything to me.”

Breyer reminded his colleagues that when the court jettisons precedent, it’s usually to right an egregious or basic wrong, such as the Plessy v. Ferguson precedent justifying segregation. “I don’t see anything too basic in the lines you’re drawing,” he told Carvin.

Carvin invoked Thomas Jefferson, saying the third president thought it “sinful and tyrannical” to require “people to give money which they don’t wish to give.”

It’s not known how Jefferson would have felt about public-sector unions. But what’s sinful and tyrannical is for billionaires to take over the electoral process and the government — and for the highest court in the land to take aim at the last remaining counterweight.

Twitter: @Milbank

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