(Bloomberg) -- The U.S. Supreme Court put on hold rulings that ordered the redrawing of Republican-friendly voting maps in Ohio and Michigan.

The high court action Friday, without published dissent, comes as the justices prepare to rule on two other cases that could insulate partisan gerrymanders from legal attack. The court heard arguments in March in gerrymandering cases from North Carolina and Maryland and is scheduled to rule on them by the end of June.

Separate three-judge panels found that Ohio’s congressional map and Michigan’s congressional and state legislative maps were so partisan they violated the Constitution. Both courts had begun setting deadlines for redrawing the maps to ensure that new district lines would be in place for the 2020 election.

The Ohio map has given Republicans 12 of 16 congressional seats in every election since the district lines were put in place after the 2010 census. It includes several bizarrely shaped districts, including one along Lake Erie that has been dubbed "the snake on the lake."

Two Republican-held districts near Cincinnati split the area in what the three-judge panel described as a "strange, squiggly, curving shape, dividing its Democratic voters and preventing them from forming a coherent voting bloc."

The Michigan fight centers on 34 congressional and state legislative districts. The three judges in that case ruled that 27 districts were unconstitutional, saying the redistricting plan as a whole had "proved tremendously successful in advantaging Republicans and disadvantaging Democrats throughout several election cycles."

The Supreme Court has never struck down a voting map as being so partisan it violates the Constitution.

To contact the reporter on this story: Greg Stohr in Washington at gstohr@bloomberg.net

To contact the editors responsible for this story: Joe Sobczyk at jsobczyk@bloomberg.net, Laurie Asséo, Max Berley

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