House Democrats hoping to retake the majority in 2012 are looking to an unlikely source for assistance: conservative primary challengers to sitting Republicans.

While just seven Republican incumbents have credible primary opponents so far, several more could face insurgent challengers. Some of those districts are safe GOP territory, while others represent potential Democratic pickup opportunities.

“Republicans have spent the last 300 days pushing an extreme agenda that caters to their tea party base in primaries while alienating independent voters,” Democratic Congressional Campaign Committee spokesman Jesse Ferguson said in a statement.

Like last year’s upset Senate GOP primary in Delaware, where tea-party-backed Christine O’Donnell lost in the general and cost Republicans a pickup opportunity, political observers note another conservative wave in primaries could hurt the GOP. Members such as Rep. Kenny Marchant (Texas) have drawn primary opponents and so have freshmen such as Rep. Chuck Fleischmann (Tenn.).

Political observers predict outside groups that played major roles in Senate primaries last year, including in Delaware, Utah and Florida, could turn their focus to the House. The Club for Growth, for example, has closely tracked Members’ votes on spending bills and the debt limit and could seek to punish the conservatively impure.

“There are going to be a lot of opportunities for the club to educate the pro-growth record, or lack of one, for many freshman Members of Congress,” spokesman Barney Keller said. “There are certainly Members of Congress who have been a disappointment, and there are others who have done excellent jobs. And we’ll be working to replace the ones who have not done as well as freshmen.”

Republicans are quick to note that just a few GOP challengers are viable candidates and that others will face only token opposition. They note that scores of GOP freshmen fought through tough primaries in 2010 and are battle-tested. They also point out that some Democrats, such as Illinois Rep. Jesse Jackson Jr., have primary challenges, too.

“Primaries are a healthy and expected part of the process for both parties and one that only a handful of Republicans are facing,” National Republican Congressional Committee spokesman Paul Lindsay said in a statement.

Republican leaders have to walk a fine line between defending their incumbents and not appearing to strong-arm the electoral process. During a C-SPAN interview last month, NRCC Chairman Pete Sessions (Texas) said, “It’s a natural thing for [a] brand-new Member of Congress to be challenged his first time out.

“We expect that internally,” Sessions said of primary challenges. “And this is a healthy thing.”

Democratic aides pounced on the comment, but Republicans didn’t blink. Many conservatives are running against the Washington establishment, as they did in 2010, and the appearance of benefiting from the national party could hurt their chances back home.

Illinois Rep. Joe Walsh, who defeated Democratic Rep. Melissa Bean by 290 votes last year, agreed with Sessions that “in general, primaries are good.” Walsh is running against fellow freshman Rep. Randy Hultgren in next year’s GOP primary, thanks to redistricting, and said no matter what, the district will remain Republican.

“Is it great that I’m probably going to have to run against another Republican freshman? No. But in Illinois, the Democrats drew the map, so we have to deal with it,” Walsh said. Illinois Republicans are contesting the map in court.

Redistricting has complicated matters for both parties, particularly in districts in which two incumbents are facing off. In Illinois alone, Democrats are uncomfortably watching as Jackson begins what is sure to be a nasty primary fight against former Rep. Debbie Halvorson. The Prairie State is also home to at least two examples of sitting Republican Members running against one another; along with Walsh and Hultgren, GOP Reps. Don Manzullo and Adam Kinzinger will likely run against each other. Still, Republican aides say, the party will defend its incumbents. Speaker John Boehner (R-Ohio) has done fundraising events for Members from Indiana, Texas and Illinois, and he assured the rank and file at last week’s Conference meeting that “we stand up for our own.”

“Speaker Boehner is very team-oriented, and he’s made helping out our Members a top priority,” spokesman Cory Fritz said. “We’ll continue to do everything we can to make sure House Republicans have the resources they need to take our conservative, pro-jobs message directly to voters in 2012.”

Fleischmann is one freshman to receive Boehner’s help. The Speaker appeared at a fundraiser in Tennessee last week for the first-term lawmaker, who took 30 percent in last year’s crowded primary and beat back a host of tea party challengers. He is attracting potential challengers from the right again, including former Rep. Zach Wamp’s son Weston Wamp.

“I’m doing my job every day, haven’t missed a vote, working in committee, getting the job done, loving the job,” Fleischmann said.

Primaries, he added, get “fresh ideas out there. It keeps people on their toes. I welcome any and all challengers, and I think it’s good for the process.”

Correction: Nov. 3, 2011

An earlier version of this article incorrectly stated that Rep. Leonard Lance (R-N.J.) has a primary opponent.

An earlier version of this article incorrectly stated that Rep. Martha Roby (R-Ala.) has a primary opponent.