Among state House races, North Carolina's efficiency gap score ranked in the top 10 most skewed of states analyzed.
Republished with permission of The Associated Press.
The AP analyzed the results of last fall's USA and state House elections across the nation, examining the percentage of races lacking major party opposition and calculating state partisan advantages using a statistical method created to detect potential political gerrymandering.
A political mapmaking process controlled by Ohio Republicans resulted in the party winning almost 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 an analysis by The Associated Press.
Republicans won 64 out of 100 seats, giving them a majority for the first time in almost 100 years.
Traditional battlegrounds such as Michigan, North Carolina, Pennsylvania, Wisconsin, Florida and Virginia were among those with significant Republican advantages in their US or state House races. That was especially true after the 2010 census, when new Republican majorities took control of the redistricting process. And only four other states had a lower percentage of contested races in 2016, when most states held state House elections, according to the AP's analysis. For some candidates - such as Republican Rep. Craig Redmon in northeastern Missouri and Democratic Rep. Gail McCann Beatty in Kansas City - 2016 marked the third straight election in which they were the only choice on the ballot.
Betty Sutton, another northeast Ohio Democrat who lost her congressional seat in that redistricting, said her district was "a flawless example of partisan efforts to rig the system".
The AP used a mathematical formula to determine the effects of gerrymandering, in which the party in power alters voting districts to its advantage, in federal and state legislative races across the country. The Republican edge in Michigan's state House districts had only a 1-in-16,000 probability of occurring by chance; in Wisconsin's Assembly districts, there was a mere 1-in-60,000 likelihood of it happening randomly, the analysis found.
Gerrymandering in congressional redistricting is not an issue in Wyoming, which has a single at-large U.S. House district won previous year by Republican Liz Cheney, the daughter of former Vice President Dick Cheney. The U.S. Supreme Court has agreed to hear an appeal.
The analysis examined the share of votes cast for Republican and Democratic candidates in each district and projected the expected number of seats each party would gain if districts were drawn so that neither party had an overall advantage.
MI provides a good example of how the formula works. Florida was found to be one of the states with the largest Republican tilts in the state House.
Other districts - such as Beatty's, where 9 of every 10 voters favor Democrats - are virtually impossible for Republicans to win.
"With an increasing number of districts being drawn to deliberately favor one party over another - and with fewer voters indicating an interest in crossover voting - lots of potential candidates will look at those previous results and come to a conclusion that it's too hard to mount an election campaign in a district where their party is the minority", said John McGlennon, a longtime professor of government and public policy at the College of William & Mary in Williamsburg., Va.