CHICAGO — A judge on Thursday blocked a set of laws pushed through late last year by Republican legislators in Wisconsin that aimed to weaken the power of the state’s newly elected Democratic governor and attorney general, setting off a bitter fight in the state.

The judge, Richard Niess of Dane County Circuit Court, issued a temporary injunction on the laws, which included curbing the authority of the incoming governor, Tony Evers, in the rule-making process and limiting the power of Josh Kaul, the new attorney general.

The judge said that the Republican lawmakers’ last-minute meeting — a December session just after the election but before the new Democrats could be sworn in — did not meet the requirements of Wisconsin law. And so the measures that emerged from it, he said, “cannot stand.” The case had been brought to court by several individuals and groups, including the League of Women Voters, Disability Rights Wisconsin and Black Leaders Organizing for Communities.

Efforts last year by lawmakers in Wisconsin and in other states, including Michigan, to weaken the power of new leaders who won elections in November set off a flurry of angry protests and, in Wisconsin, several lawsuits.