The leaders of four major public-sector unions slammed the Supreme Court's decision Thursday to take up the case of Janus vs. American Federation of State, County and Municipal Employees.

They denounced Janus as a "political effort to further rig the rules against working people" but declined to directly address the issue in the case, which involves the unions' right to take dues money from people who do not want to support them.

"The Janus case is a blatantly political and well-funded plot to use the highest court in the land to further rig the economic rules against everyday working people. The billionaire CEOs and corporate interests behind this case, and the politicians who do their bidding, have teamed up to deliver yet another attack on working people by striking at the freedom to come together in strong unions. The forces behind this case know that by joining together in strong unions, working people are able to win the power and voice they need to level the economic and political playing field. However, the people behind this case simply do not believe that working people deserve the same freedoms they have: to negotiate a fair return on their work," the union leaders said.

The statement was issued jointly by AFSCME President Lee Saunders, American Federation of Teachers President Randi Weingarten, National Education Association President Lily Eskelen Garcia and Service Employees International Union President Mary Kay Henry.

The statement did not address the details in the case, which asks whether Mark Janus, an Illinois state government employee, can be forced to regularly pay a "security fee" to the union as a condition of employment. Janus argues the requirement violates his First Amendment amendments.

None of the unions had responded to a question from the Washington Examiner: "Should it be the individual worker's right to decide whether they join or otherwise support a union?"

Security fees are a common provision in public-sector union contracts. Unions such as AFSCME count on those fees for revenue. An internal survey the union did in 2015 found that only one-third of its members would voluntarily pay dues no matter what and half of its membership couldn't be counted upon to do that. Fifteen percent said they would opt out of paying dues.

Unions argue that they are owed the fees to compensate for their collective bargaining on behalf of the workers. The Supreme Court ruled that such fees were legal in a 1977 case called Abood v. Detroit Board of Education. In the 2016 term, the justices appeared to be on the verge of overturning Abood in a case called Friedrichs v. California Teachers Association but Justice Antonin Scalia's death resulted in a 4-4 deadlock.

The unions stressed that Abood has been unchallenged for decades. "Under the guise of the First Amendment, [powerful interests] want to overturn a 40-year precedent that's been reaffirmed numerous times. In other words, this would be a radical departure from well-established law. We believe that after resolving a similar case last year, the Supreme Court erred in granting cert in Janus, and that the trumped-up underpinnings of the plaintiff's argument will rapidly become clear before the full bench," Weingarten said.

Terry Pell, president of the Center for Individual Rights, which argued Friedrichs before the Supreme Court, saw it differently: "We are watching closely and hopeful that Janus will receive a favorable ruling, opening the door ... to help end – once and for all – the unconstitutional practice of compelled support for unions for millions of public-sector workers."