Because Mitch McConnell and Senate Republicans declared President Barack Obama's Constitution-mandated duty to nominate Supreme Court justices null and void during the last full year of his tenure—under the simple premise that their own party's power was more important—the court has been working off the resulting backlog of cases now that a new president of McConnell's party has been elected and the vacancy was filled in accordance to McConnell's personal wishes.
His efforts to bend the country to his ideological will, which will come up in the history books alongside the usual paragraphs about Joe McCarthy and George Wallace, presuming the nation ever again comes to its senses, are now paying the expected dividends. With the addition of the archconservative Neil Gorsuch, the court will now be hearing a case that may cripple labor rights for federal workers for a generation.
After the justices deadlocked 4-4 in a similar case last year, the high court will consider a free-speech challenge from workers who object to paying money to unions they don’t support.
The court, with conservative Justice Neil Gorsuch on board, could decide to overturn a 40-year-old Supreme Court ruling that allows public sector unions to collect fees from non-members to cover the costs of negotiating contracts for all employees.
The Janus case hinges on whether so-called "right to work" rules should apply to the entire federal government, effectively nullifying the ability of each union to collect mandatory member dues to support collective bargaining efforts on behalf of those employees. Conservative forces have chafed at the rule for decades, almost entirely because unionized workers tend to broadly support Democratic ideas over Republican ones and unions are very effective advocates for those ideas, and see the chance to cripple those unions permanently with the addition of Gorsuch.
Gorsuch, you may recall, is the "textualist" who argued that an employee of a trucking company could be fired for saving his own life, which is the sort of cartoonish buffoonery Mitch McConnell had been holding a court seat open for to begin with. He is expected to have open contempt for the arguments of the labor unions because that is exactly why the Republican Senate declared the United States Constitution to have new, invisible subclauses that were never discovered before and will never be discovered again. He is the asterisk that will make sure the unions are punished for Democratic support.
Unions are therefore expecting the worst from the now fully staffed court. The question is not whether the conservative wing of the court will overturn decades of established labor law, but how many decades they will attempt to erase in one blow.