The political world is abuzz about the presidential primaries, but more than a few members of Congress are far more worried about their own primaries.

A small news item in the Marion, Ind., Chronicle-Tribune over the weekend detailed that Rep. Dan Burton (R-Ind.) is expanding his mobile office schedule to connect better with constituents.

Making sure voters are getting their needs tended to is always important for lawmakers, but this cycle it is even more so.

With congressional approval ratings in the tank, a recession looming and presidential candidates repeatedly saying Washington is broken, incumbents are nervous — very nervous.

Burton last January attracted criticism for missing House floor votes because he was off playing in a celebrity golf tournament in Palm Springs, Calif.

Soon thereafter, a primary challenger, physician John McGoff, emerged to challenge the incumbent. McGoff seized on the missed votes to make his case that the 13th-term lawmaker should be replaced in the conservative 5th district.

Burton apologized for going off on his jaunt and missing the votes. He has kept his clubs in the closet this month and has been present for most votes in the second session of the 110th Congress. He is not considered one of the most vulnerable members to a primary challenge, having a large cash advantage over McGoff. Still, he is clearly looking in his rearview mirror.

The Indiana lawmaker is not alone. Reps. Wayne Gilchrest (R-Md.), Daniel Lipinski (D-Ill.), Jean Schmidt (R-Ohio), Albert Wynn (D-Md.) and others are campaigning hard in primaries.

Just this month, Wynn sent out releases criticizing his primary opponent Donna Edwards’s “dirty tricks,” pointing out his participation in a labor rally and touting Planned Parenthood’s endorsement of his candidacy. Wynn narrowly defeated Edwards in the 2006 primary amid an intense spotlight on his 2002 vote for the Iraq war.

Wynn has since moved left on the war, supporting Rep. Dennis Kucinich’s (D-Ohio) measure calling for the impeachment of Vice President Cheney.

In normal election cycles, incumbents skate through primary season without serious challengers. This cycle appears to be different.

Legislators on Capitol Hill know they are being targeted and primary fears are making members work harder to secure votes from their constituents, which in most cases is a good thing.

Super Tuesday will generate a ton of politically rich stories, but some lawmakers will be paying close attention down-ballot to see whether Lipinski survives his challenge that day. The following week, Maryland voters will make clear their satisfaction, or lack thereof, with Gilchrest and Wynn. And in early March, Schmidt faces her primary test.

Burton’s primary election doesn’t come until May 6. But by then, he may be expanding his mobile office hours even more.