Emboldened by a number of victories over incumbents and establishment-backed candidates last cycle, Republican candidates across the country have set their sights on defeating GOP incumbents in 2012 primaries.

WASHINGTON, DC - SEPTEMBER 12: Republican presidential candidate Rep. Thaddeus McCotter (R-MI) speaks during a news conference on Capitol Hill on September 12, 2011 in Washington, DC. (Photo by Mark Wilson/Getty Images) (Mark Wilson/GETTY IMAGES)

But that hasn’t stopped a bunch of tea party activists and otherwise ambitious challengers from stepping forward early in the 2012 election cycle.

The challengers and potential challengers range from state legislators readying to run against freshmen Reps. Scott Desjarlais (R-Tenn.) and Nan Hayworth (R-N.Y.) and aborted presidential candidate Rep. Thaddeus McCotter (R-Mich.), to grassroots activists looking to become the next Rep. Trey Gowdy (R-S.C.) or Rep. Mo Brooks (R-Ala.) – the two House GOP freshmen who unseated incumbents in primaries last year.

(Two House Democrats were also unseated in primaries in 2010, while three senators lost primaries — two Republicans and one Democrat.)

And despite the undistinguished political careers of some of their challengers, many incumbents are feeling a little uneasy – in part, no doubt, because some of them will defend districts that are somewhat different than after redistricting.

“Is it enough to motivate folks? Yeah. Is it a widespread concern? No,” said a GOP strategist.

Many of the incumbents facing primaries have seen them before. Rep. Dan Burton (R-Ind.), who won with less than 30 percent of the vote in his 2010 primary, is again being targeted be several formidable foes. And Reps. Alan Nunnelee (R-Miss.), Larry Bucshon (R-Ind.), Tom Graves (R-Ga.) and Chuck Fleischmann (R-Tenn.) all could face opponents they dispatched in 2010 primaries – sometimes by small margins.

But others are getting their first taste of what’s it’s like to be on the other end of a tea party challenge.

Rep. Brian Bilbray (R-Calif.), who hasn’t faced a primary since returning to Congress in 2006, is getting called a “RINO” – a.k.a. “Republican in Name Only,” by a local tea party activist who has bought an hour-long slot on a local radio station.

An aide to tea party Sen. Rand Paul (R-Ky.) is challenging another member of Congress, Rep. Tim Murphy (R-Pa.), who hasn’t faced a primary in any of his House races, including when he was elected in 2002. The challenger, 27-year-old Evan Feinberg, has been grabbing a fair amount of headlines over the past week, and RedState.com founder Erick Erickson has made defeating Murphy a pet project.

And Murphy’s fellow moderate Pennsylvanian, Rep. Mike Fitzpatrick (R), faces his own potential challenge from a staffer for the tea party-aligned group Americans for Prosperity, Jennifer Stefano. Stefano cites Fitzpatrick’s vote against a GOP-sponsored labor bill.

But even in 2010 – supposed by many a political analyst to be an anti-incumbent year – just three incumbent senators and four incumbent House members lost primaries, and the vast majority of incumbents went unopposed in their primaries. So even if people are in more of a kick-the-bums-out mood than they were even in 2010, most, if not all, of these incumbents are likely to survive.

But just the prospect of becoming the latest incumbent to draw the ire of the tea party can be enough to get the safest of incumbents to ramp up his or her campaign a little early.

And given Congress’s ill repute, members really can’t start warding off these potential challenges too early.