State lawmakers who reconfigured congressional maps to benefit one party over another have drawn themselves into a corner in some House districts.
A handful of the newly redrawn districts are either controlled by the other party or are more competitive than expected.
Partisan redistricting following the 2000 census largely succeeded in eliminating most close races. In these instances, supporters of a state's minority party were packed into a few districts, maximizing the majority's clout in neighboring ones.
Yet in a few cases, state legislatures may have overreached, proving that drawing new political boundaries is hardly an exact science.
"The greedier you are with a partisan gerrymander, the less likely you are to get every seat you want," said Nathaniel Persily, a University of Pennsylvania law professor and redistricting expert. "One of the risks is if you spread your supporters too thin, you end up losing several seats."
The biggest test case this year is Texas. Republicans led by House Majority Leader Tom DeLay came up with a radical design to push five Democratic congressmen into competitive races in GOP-friendly districts.
Georgia may be the most compelling example of partisan overshooting.
When things go wrong
When the state picked up two new congressional seats in the 2000 census, Democrats in charge of the state's redistricting process redrew the map, hoping to transform an 8-3 GOP advantage into a 7-6 Democratic edge.
They enticed Rep. Bob Barr to leave his seat to challenge fellow Republican Rep. John Linder in a neighboring district; Linder won easily. But Republicans kept Barr's seat anyway, and the district's new congressman, Phil Gingrey, figures to win re-election easily over Democrat Rick Crawford.
After the voting two years ago, Republicans still had eight seats, and Democrats five. Gingrey said the strategy clearly backfired on Democrats.
"It was a desperation move to hold onto power when the people were sending another message," said Gingrey, whose district has 17 counties, 10 of which are represented by multiple congressmen. "They basically stacked the deck, tried to slice and dice it, and the public be damned."
The races for two other Georgia seats altered by redistricting could be among the closest in the country even though Democrats drew the lines for themselves.
Republican college professor Max Burns two years ago shocked Champ Walker, the son of a former Democratic state Senate leader. Democrats figure their candidate this time, lawyer John Barrow, is stronger than Walker, whose record included arrests for shoplifting and driving with a suspended license. Burns, however, has a huge financial edge.
In Georgia's 3rd District, Democrat Jim Marshall again faces Republican Calder Clay after beating him narrowly in 2002. A Clay victory could be devastating for Georgia's Democratic Party, which saw Gov. Roy Barnes and Sen. Max Cleland lose on a disastrous election night for the party two years ago.
In Pennsylvania, six-term Democratic Rep. Tim Holden is favored to hold onto his seat against Republican lawyer Scott Paterno, the son of Penn State football coach Joe Paterno. This certainly was not what Republicans intended when they redrew the district to pit Holden against former Republican Rep. George Gekas in 2002, figuring Holden would drop out.
Not only did Holden stay in that race, but he beat Gekas in the biggest shocker of four incumbent versus incumbent matchups in the state.
Bruce Andrews, who was Holden's campaign manager in 2002, says Pennsylvania Republicans made a redistricting mistake they will regret for years.
"They tried to maximize the number of Republican seats, and they got greedy," Andrews said.
Before the last election, Utah Republicans used redistricting to take a swing at Jim Matheson, the state's lone Democratic congressman. Republican John Swallow lost to Matheson by less than 1,600 votes and is trying to beat him again this year.