Ohio Gov. John Kasich on Tuesday joined friend and ex-California Gov. Arnold Schwarzenegger's effort to overhaul partisan political map-making that's helped fuel their own Republican party's rise to power.

Kasich signed onto a legal brief that opposes the GOP in the momentous redistricting case being heard by the U.S. Supreme Court this fall. He said other signers include Republicans John McCain, Richard Lugar and Bob Dole. At issue is whether Republican lawmakers in Wisconsin drew legislative districts that favored their party and were so out of whack with the state's political breakdown that they violated Democratic voters' constitutional rights.

Kasich, a 2016 presidential contender, is a frequent critic of President Donald Trump, who was a GOP primary opponent, and has parted with fellow Republicans on some big issues, including Medicaid expansion under the Affordable Care Act. He said his decision to add his voice to a growing list of leaders opposing how U.S. political maps are made wasn't about party.

"I've decided to join because I think what we have witnessed over time here is the fact that the drawing of these districts in a gerrymandered way, coupled with the newfound activism of the people, has just driven the Congress farther and farther apart," he said. "And I think the time has come for the court to be able to make a big statement about the way in which we draw these districts."

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Schwarzenegger and Kasich have long argued that partisan gerrymandering is contributing to dysfunction in Washington.

An AP analysis published in June of the outcomes of all 435 U.S. House races and about 4,700 state House and Assembly seats up for election last year found four times as many states with Republican-skewed state House or Assembly districts as Democratic ones. Among the two dozen most populated states that determine the vast majority of Congress, there were nearly three times as many with Republican-tilted U.S. House districts.

In Ohio, the Republican-controlled map-making system resulted in the party winning nearly two more U.S. House seats and five more Ohio House seats in the last election than would have been expected in neutral circumstances, according to the AP analysis. In congressional races, Republican candidates won 56 percent of the vote in Ohio but 75 percent of the seats.

Kasich said "safe" districts no longer do what they did in the past: afford politicians the comfort to concentrate on policy. Instead, they open up more centrist politicians to primary challenges from their parties' more extreme flanks, he said.

Schwarzenegger is working to combat the gerrymandering through his Terminate Gerrymandering Crowdpac. Kasich said Schwarzenegger reached out to him to sign the brief, which is part of his efforts.

Ohio has seen growing bipartisan concern about how its voting districts are drawn.

Kasich said he is pleased that Ohio has moved to reform its legislative map-making system. Ohio residents voted overwhelmingly in 2015, after a decade of false starts, to approve new rules for drawing state legislative districts that aimed to reduce gerrymandering.

Kasich said he hopes congressional districts aren't far behind. Backers in the Republican-controlled state Legislature have been working on the idea of replacing a process that gives the state Legislature power to approve the congressional maps drawn once every 10 years.