WASHINGTON — The Supreme Court on Monday refused separate requests from Republicans in North Carolina and Pennsylvania to block new congressional maps approved by courts in those states, meaning the fall elections will be held in districts more favorable to Democrats than the ones created by the Republican-led legislatures.

North Carolina’s Republican leaders had asked the high court to embrace an unprecedented theory that the state’s judiciary could not impose a new map for congressional elections, even though it found the legislature’s version had violated the state’s guarantee of free and fair elections. The U.S. Constitution, they argued, leaves that question in the hands of the legislature, not courts.

Three of the court’s conservatives said they were anxious to consider such an argument. But a fourth who also expressed interest said it was too close to the election to upend planning for primaries.

In the Pennsylvania case, the court turned down a request to intervene in the state Supreme Court’s decision to impose a map after the Democratic governor vetoed a map passed by the legislature, which is controlled by Republicans. The challenge was brought by Republican voters and candidates.

North Carolina is a purple state, with a legislature controlled by Republicans, a Democratic governor and an elected state Supreme Court with four Democrats and three Republicans. Donald Trump won the state in 2020 by a 50 percent to 49 percent margin over Joe Biden.

The four Democrats on the state Supreme Court said the redistricting maps passed by the legislature after the 2020 Census had a partisan tilt “not explained by the political geography of North Carolina.”

The court concluded the maps “are unconstitutional beyond a reasonable doubt under the free elections clause, the equal protection clause, the free speech clause, and the freedom of assembly clause of the North Carolina Constitution.”