FREDERICK, Md. — Rep. Roscoe G. Bartlett lost the battle for his political life Tuesday, failing in his bid to win an 11th term in a Maryland district that has long shared his values but has changed drastically as a result of gerrymandering.
The 86-year-old Republican’s 6th District was redrawn last year by Democrats in this deep-blue state’s legislature, which removed roughly half its residents and instituted a Democratic majority. The changes let Democrat John K. Delaney win the race and give his party a seventh of Maryland’s eight House seats.
State lawmakers in several other Democratic states took the same approach to this year’s elections, seeking to force out Republicans and close in on the GOP’s House majority. Republicans also did their share of gerrymandering but focused largely on fortifying incumbents’ districts to retain their majority.
House Democrats were expected to gain a handful of seats on Election Day but fell well short of erasing Republicans’ 50-seat advantage in the 435-member chamber.
Mr. Bartlett’s seat had been widely expected to go from red to blue, making him one of the nation’s most vulnerable incumbents.
“We had the most gerrymandered district in the country,” Mr. Bartlett said Tuesday night after the race was called. “A year ago, I had a decision to make. The easy thing would have been to just retire, but I was told that our chances of holding the seat were better if I ran for it.”
Maryland’s map has been criticized by political observers as one of the nation’s most blatantly partisan, joining a list that included Illinois’ new map which was drawn by the state’s Democratic governor and legislature.
The map appeared poised to force out GOP Rep. Joe Walsh, a freshman tea party member who was drawn out of his old district last year but ran for re-election anyway, as an underdog against Democrat Tammy Duckworth. With about half the vote counted Tuesday night, Ms. Duckworth led by 55 percent to 45 percent.
In an effort to cut down the GOP’s 11-8 advantage in seats, Illinois Democrats also made re-election much tougher for incumbent Republican Reps. Judy Biggert, Robert J. Dold and Robert T. Schilling, all of whom faced stiff challenges Tuesday though none of the races were decided early in the evening.
Redistricting in some Republican-led states also had a clear partisan effect on this year’s elections.
In Virginia, the majority-Republican General Assembly and Gov. Bob McDonnell drew a map designed to make virtually all 11 congressional districts less competitive, and apparently succeeded, as all eight of the party’s incumbents House members won.
The map fortified several Republican districts in part by stacking Democratic voters in the state’s few blue districts, such as Democratic Rep. Robert C. “Bobby” Scott’s majority-black 3rd District.
Ohio and Pennsylvania Republicans also passed maps that were expected to protect their incumbents, including Pennsylvania Republican Rep. Lou Barletta, whose formerly Democratic-leaning district was redrawn to be solidly conservative.
One place where Republicans were more aggressive was in North Carolina, where the GOP seized control of both state legislative chambers for the first time in 140 years and responded by pushing through a map that altered the Democrats’ 7-6 House advantage to an 8-3 deficit with two races still undecided Tuesday night.
Republicans unseated Democratic Rep. Larry Kissell and were running strong for the two seats being vacated by retiring Reps. Brad Miller and Heath Shuler.
Todd Eberly, director of public policy studies at St. Mary’s College of Maryland, said Republicans have mostly sought to protect their existing seats because many sense they have reached their “high-water mark” after picking up 63 seats in the 2010 midterm elections.
He said the GOP’s conservative approach was a smart political move that could put the party in place to hold a majority over the next decade.
“It’s been drawn to such an extent that you’re not likely to see a lot of change,” Mr. Eberly said, adding that he considers 380 of 435 seats to be safely in favor of one party or the other. “If that number doesn’t make it clear, I don’t think anything would.”
Many activists have called for nonpartisan or bipartisan commissions to handle redistricting, and while a few states have obliged, the approach has not cured bickering between parties.
In Arizona, the state’s nonpartisan Independent Redistricting Commission drew a map that state Republicans blasted as biased. The party unsuccessfully sued to have the map withdrawn and Republican Gov. Jan Brewer tried to fire the commission’s chairman, only to have the move blocked by the state Supreme Court.
In California, a bipartisan citizens’ commission approved a map that was expected to make more of the state’s 53 districts competitive, but which many analysts predicted would give Democrats a chance of gaining a couple of seats.
Mr. Eberly acknowledged that nonpolitical commissions are not a cure-all, but he said he thinks that such an approach combined with laws designed to make districts more compact would be a step forward for most states.
“No matter what you do to try and shield out politics, things can happen,” he said. “But anything along those steps makes it more difficult.”