COLUMBUS, Ohio » Of 435 House races in November, only a few dozen were considered competitive – a result of decades of drawing district lines for partisan advantage, generally by state legislatures.

But in an era of hyperpartisan gerrymandering, which many blame for the polarization of state and national politics, Ohio took a step in the opposite direction last week. With the support of both parties, the Ohio House gave final approval Wednesday to a plan to draw voting districts for the General Assembly using a bipartisan process, intended to make elections more competitive.

"I think it will be a new day in Ohio," said Rep. Matt Huffman, a Republican who shepherded the plan.

While the proposal is aimed narrowly at state legislative districts, it could have an indirect impact on congressional districts because they are drawn by state lawmakers. President Barack Obama carried Ohio, a quintessential swing state, by two percentage points in 2012. Yet Republicans have overwhelming majorities in Columbus, the capital, and a 12-to-4 advantage in congressional seats.

"When you’re an outsider looking in, it’s almost shocking," said Sen. Joe Schiavoni, the Democratic leader in the state Senate.

The plan explicitly prohibits maps drawn to favor or disfavor one party.

Republicans, who in some ways acted against their own interests, were motivated partly out of fear of a potential voter referendum that could impose an even more sweeping overhaul.

They also recognized that they could slip into the minority one day.

"Right now, we’ve got 65 of 99 seats in the House and 12 of 16 congressmen," Huffman said. "But in a state like Ohio, that’s not always going to be the case."

The proposed changes, which Ohioans must vote on in a November 2015 referendum to amend the state Constitution, would not go into effect until the next redistricting, in 2021.

In 2010, national Republicans mounted a major effort to capture statehouses in the midterm elections, with their eye on controlling the redrafting of district maps that follows each census. They succeeded in many places. Presidential battlegrounds like North Carolina, Ohio, Pennsylvania and Virginia send many more Republicans than Democrats to Congress, a factor in the party’s ability to gain and then increase its majority in the House over the last three elections.

No state has moved more significantly than Ohio since 2012 to take raw partisanship out of the process, said Morgan Cullen, a policy analyst at the National Conference of State Legislatures.

Jon Husted, Ohio’s secretary of state and a Republican, praised the plan as a step toward ending polarization in the General Assembly. Many members face competition only in primaries, pushing them to cater to ideological extremes.

"We elect people that get there by winning primaries, and we say, ‘Now you come together and do the people’s business,’" Husted, a former speaker of the State House, said. "If your electoral incentive is only to care about staying loyal to the base voter in a primary election," he added, "then your incentive to govern" is small.

Sen. Nina Turner, a Democrat who unsuccessfully challenged Husted for secretary of state last month, said she thought the plan would create a more balanced General Assembly.

"I always say Ohio is conservative by design and not by desire," she said. "This really is a tremendous deal."

But some Democrats said the change did not go far enough because it excluded congressional maps.

Republicans said that was because of the chance that the U.S. Supreme Court would invalidate an overhaul in a ruling expected next year. Lawmakers in Arizona are suing to reverse a ballot initiative that took the congressional map-drawing decision out of the hands of the Legislature and gave it to an independent commission.

In 37 states, legislatures now draw voting maps. The 13 others use commissions that are, in theory, less partisan. In some states, the commissions are independent, and in others, their members are politically appointed. That has been Ohio’s system since the 1970s. The Apportionment Board is composed of three elected state officials – the governor, auditor and secretary of state – and one member from each party chosen by the legislature. Republicans have controlled it for three decades.

The new plan would add two members, one from each party. And if the minority-party members did not approve of the district maps, the changes would last only four years, not the traditional 10. Partisan control of the board could seesaw in four years after statewide elections, so this would create an incentive to win the minority’s approval.

"I always remind folks that just because it’s worked for us for 30 years doesn’t mean we might not lose the Apportionment Board, and it would be used against you with the same efficiency you used it," Husted said.

Still, there is no guarantee the plan would lead to a more politically balanced or moderate legislature. Americans have increasingly sorted themselves into communities that are ideologically like-minded, political scientists say. In rural and urban areas alike, the chances that voters of opposite parties live near each other have diminished.

California, which introduced a rigorously fair redistricting process before the 2010 census, is an object lesson. There, a 14-member, multipartisan commission draws district lines. In 2012, using new maps, Democrats enlarged their supermajorities in the Legislature.

"There’s no perfect map, no panacea," said Cullen, of the National Conference of State Legislatures.

Two nonpartisan groups that have pushed for decades for changes in Ohio, the League of Women Voters and Common Cause, praised the plan to a point. It "makes significant strides to address gerrymandering of state legislative districts," Ann E. Henkener of the League of Women Voters said in a statement, but "we are disappointed that it leaves out Congress."

On Wednesday, after the House overwhelmingly passed the final version of the proposal on its last day of business for the year, members broke into applause. Speaker William G. Batchelder, a Republican, stayed his gavel as he told lawmakers, "I’m not going to mention I’m not meant to allow that, because it was so damn refreshing."

Trip Gabriel, New York Times

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