The Supreme Court  is poised to deal a sharp blow to the unions that represent millions of teachers and other public employees, announcing Thursday it will consider striking down the mandatory fees that support collective bargaining. The justices will hear the case of Mark Janus, an Illinois state employee who objects to paying fees to the union, which represents 35,000 state workers.

When Republicans in Kentucky seized total control of the state government  last year, Damon Thayer, the majority leader in the State Senate, began asking around for advice from counterparts in other capitals where the party already dominated both the legislative and executive branches. How should we handle all this power? he wanted to know. One answer impressed him, Mr. Thayer said, from a senior Republican lawmaker in Wisconsin: “Move quickly.” Kentucky Republicans have done just that, swiftly passing laws to roll back the powers of labor unions and restrict access to abortion.

Republicans stormed to power in state elections across the country in November on a promise to take on the establishment and return  government to the average citizen. But in state capitals where they gained control, they moved quickly to do something else entirely: They’ve consolidated their newfound power — and rewarded their corporate donors — by delivering death blows to a  longtime enemy: organized labor.

President-elect Donald Trump and the Republican-controlled Congress are drawing up plans to take on the government bureaucracy they have long railed against, by eroding job protections and grinding down benefits that federal workers have received for a generation. Hiring freezes, an end to automatic raises, a green light to fire poor performers, a ban on union business on the government’s dime and less generous pensions — these are the contours of the blueprint emerging under Republican control of Washington in January.