Congress’s lines are being redrawn, putting some longtime incumbents in a tough spot heading into next year’s election. Due to population shifts and partisan interests, some congressional districts are undergoing extreme makeovers, forcing their representatives to run in unfamiliar and sometimes inhospitable territory. Here are the five most vulnerable Republican incumbents.

#5: Robert Dold (R-Ill.)
The freshman won a Democratic-leaning suburban Chicago district in 2010 by a narrow three-point margin, and Democrats who controlled Illinois’s redistricting process have pushed the district further out into the suburbs, made it a bit more Democratic, and removed some of the ticket-splitting swing voters that had allowed him to win. His old district gave favorite son President Obama 61 percent of its vote in 2008; the new one would have given him about 63 percent of its vote.


#4: Ed Royce (R-Calif.)
California’s new map has one less Republican district in the Orange County area, and Royce will likely have to face off with Rep. Gary Miller (R-Calif.) in a primary in order to stay in Congress. His more-conservative voting record would normally give him the upper hand, but a new California law that creates all-party primaries and general elections between the top two vote-getters means that the two would face off in a district that contains much more of Miller’s old territory and an electorate that could reward the more moderate candidate.

#3: Judy Biggert (R-Ill.)

Like Dold and many other Republicans in Illinois, Biggert’s district was greatly altered by a Democratic gerrymander. The centrist Republican would have a tough time winning a Republican primary in the few GOP-leaning districts left in greater Chicagoland, and is likely to retire.

#2: David Dreier (R-Calif.)
Dreier’s district was carefully gerrymandered to be solidly Republican ten years ago, but the area east of Los Angeles has become significantly more Hispanic and the state’s new Bipartisan Redistricting Commission radically altered the map. Dreier’s best hope is if Rep. Jerry Lewis (R-Calif.) retires. If that doesn’t happen he could have to run in a district that leans strongly Democratic.

#1: Jeff Landry (R-La.)
The freshman Tea Party favorite is a victim of his own party. Louisiana will lose a congressional district, the sole Democratic seat in the state is heavily African American and protected by the Voting Rights Act, and Landry was the odd man out as powerful Republicans protected their own in the redistricting plan. He is likely to challenge Rep. Charles BoustanyCharles William BoustanyFormer lawmakers call on leadership to focus on unity Partial disengagement based on democratic characteristics: A new era of US-China economic relations Lobbying world MORE (R-La.) in a primary, but Boustany’s allies in the statehouse were careful to make sure Landry’s political base was fractured amongst various districts so he would be less of a threat.
Honorable mentions: Republican Reps. Elton Gallegly (Calif.), Allen West (Fla.), Randy Hultgren (Ill.), Tom Latham (Iowa), Steve King (Iowa), Adam Kinzinger (Ill.), Bobby Schilling (Ill.), Joe Walsh (Ill.), Andy Harris (Md.)