The Associated Press used a new mathematical formula to scrutinize roughly 4,700 state House and Assembly seats up for election past year and found a decided advantage for Republicans in numerous states, including Idaho.
In the nationwide AP analysis, North Carolina had the highest efficiency gap - or greatest Republican advantage - among the roughly two-dozen largest states that determine the vast majority of Congress.
The evaluation released Saturday found the Nevada Assembly's 42 districts gave more favor to Democrats than the lower chamber of any other state legislature in the country in 2016. "There are some states where Republicans have clearly done extraordinary gerrymandering, we have cases here in MI, we certainly have cases in North Carolina and Texas, Democrats are not innocent, they also have dirty hands in places like Maryland".
The analysis found four times as many states with Republican-skewed state House or Assembly districts than Democratic ones, including in Virginia.
"Obviously if you're the party in power and your members wanted to draw districts that helped themselves get elected, to a certain extent that's naturally going to benefit the majority", Kottkamp noted.
Ultimately, Republicans picked up a 13th district in a state where registered Democratic voters outnumber Republicans by a margin of 4 to 3.More news: Koepka clinches first major with victory at US Open
WMU Political Science Professor Peter Weilhouwer says it played a role in some of the recent runoff elections, helping republicans stave off democratic challengers. But they point out Republicans are at this point just better at raising money, recruiting candidates and winning races in districts that should be more competitive.
More than one-third of state House races were unopposed in 2016, including 18 Republican candidates and 16 Democratic races.
Those behind the amendment successfully sued to have U.S. House and state Senate maps redrawn because they didn't meet constitutional muster, but state House maps went unchallenged. AP found a decided advantage for Republicans, including a slight one in CT.
The AP analyzed 2016 election results using a formula comparing the statewide average share of the vote that a party receives in each district with the statewide percentage of seats it wins. Chris Jones testified in federal court he tried to accommodate requests from a large majority of delegates, both Republicans and Democrats, who sought to tweak lines, sometimes to draw out precincts where they had historically performed poorly.
"I think it's a balance but again, it's also important to, at least in my mind, respect those boundary lines of the cities, towns and counties and school districts as much as possible", he said.
"When the special interests couldn't beat us at the ballot box, they stacked the district to get the result they wanted", she said.
The investigation used a new statistical method of calculating partisan advantage, developed by University of Chicago law professor Nick Stephanopoulos and Eric McGhee, a researcher at the nonpartisan Public Policy Institute of California, called the "efficiency gap". Idaho has a 13 percent efficiency gap heavily favoring Republican congressional candidates.