(Reuters) - A coalition of left-leaning Wisconsin groups filed a lawsuit on Thursday seeking to throw out several laws passed by the Republican-led legislature after the November election that weakened the powers of the newly elected Democratic governor.

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The groups, including the state League of Women Voters and other advocacy organizations, said the unusual lame-duck session was illegally convened, which would make any legislation approved during the session unlawful.

Outgoing Republican Governor Scott Walker signed the bills into law in mid-December, despite criticism from Democrats that the efforts were a last-minute power grab before Democrat Tony Evers, who defeated Walker, took office this month.

Republicans defended the moves, and similar maneuvers in Michigan and North Carolina, as good-faith efforts to ensure the legislative and executive branches remain equals and to improve state policies.

The Republican majority leader in the Wisconsin Senate, Scott Fitzgerald, called the lawsuit “frivolous,” and said both Democrats and Republicans have convened extraordinary sessions to pass legislation.

“This is nothing more than liberals yet again throwing a tantrum,” he said in a statement.

The legislation would give lawmakers, rather than the executive branch, the power to decide whether to withdraw the state from lawsuits. That measure is aimed at preventing Evers from following through on campaign promises to end Wisconsin’s challenge to the federal Affordable Care Act, popularly known as Obamacare.

The lawsuit was filed in state court in the capital, Madison. While it aims to help Evers, he is named as a defendant in his current role as governor. The lawsuit notes that Evers’ predecessor, Walker, was responsible for the relevant actions.

Republicans, who continue to control both chambers of the legislature, passed the bills around dawn on Dec. 5 following an all-night session, after protesters crying “shame” packed the halls of the capitol building the day before.

In Michigan, Republicans pursued a number of bills restricting the powers of incoming Democrats, though some of the most controversial measures either did not pass the legislature or were vetoed by outgoing Republican Governor Rick Snyder.

The lame-duck moves were reminiscent of North Carolina Republicans’ last-gasp efforts in 2016 to weaken the incoming Democratic governor, Roy Cooper, much of which has been tied up in court challenges ever since.

North Carolina’s Republican-dominated legislature pushed through a voter identification law in a lame-duck session in December, overriding Cooper’s veto. Republicans no longer have a veto-proof majority in 2019.