DES MOINES --- There is a saying in Iowa Republican political circles: GOP incumbents should spend more time looking over their right shoulder than their left as primaries approach.
That bit of political wisdom holds particularly true for the June 5 primary in which a dozen incumbents across the state face intra-party challenges.
These are not instances such as House District 50 - where incumbents Annette Sweeney and Pat Grassley were thrown together by redistricting. These are races where someone from the party is challenging a sitting incumbent.
And it's only happening on the Republican side this year.
"A lot of these challenges are being done by people and supported by groups that want their candidates to be more ideologically pure on Second Amendment and right-to-life issues," said Craig Robinson, former political director for the Iowa Republican Party. "I think it's a wakeup call for some of these incumbents. I think some of them get caught off guard."
Liberty Iowa is a new political action committee that supports candidates who promise to support abortion restrictions and Second Amendment rights.
The group has connections to former State. Rep. Kim Pearson, a Republican from Pleasant Hill, whose no-compromise attitude gained some critics in her own party during her only two-year term as a legislator.
Pearson's daughter, Morgan, is the treasurer of the group.
"Definitely, our main goal is attracting constitutional conservatives to run for office," said Joel Kurtinitis, a West Des Moines Republican who serves as Liberty Iowa's chairman.
Liberty Iowa has endorsed challenger Jeff Mullen against incumbent Sen. Pat Ward in the race for Senate District 22, but most of its public endorsements are in primaries where Republicans don't already hold a seat.
The religious conservative Family Leader group also endorsed Mullen over Ward in that race, but its other endorsements line up in favor of Republican incumbents.
Campaign disclosures show that Liberty Iowa has spent nearly all of the $5,735.50 it has raised on "postage, shipping and delivery," but it doesn't indicate to whom the funds have gone.
Former Republican House Speaker Christopher Rants has given a lot of thought to the primary landscape, and he believes that if it's not Liberty Iowa, there's a group out there working hard to oust moderate Republicans.
His blog, "Rants 3.0," goes into great detail about the similarities of letters mailed by Matthew Ung and Jake Highfill, challengers to Rep. Ron Jorgensen of Sioux City and Erik Helland of Johnston, respectively.
"I've never seen something like this," Rants said. "They're attacking candidates as not pro-life because they vote for the Health and Human Services bill because it includes Medicaid dollars, and the federal Medicaid laws say you can't discriminate on who receives that money."
Rants said the attacks "aren't honest" and believes the voting public would be better served if some of the complexity involved in the votes were explained.
"We understand that governing requires some compromise, and that's fine," Kurtinitis said. "But we want candidates who believe that compromise shouldn't be the first option on these important issues when there is a disagreement. Too often it seems like it is with some."
But being on the right is not a guarantee that you won't get challenged.
Tom Shaw, a first-term state representative from Laurens who is endorsed by the Liberty Iowa PAC and the Family Leader, is being challenged in his district by Maison Bleam, a 2009 University of Iowa graduate who works on his family farm. Bleam was recently endorsed by former state Rep. Dave Tjepkes, a ex-state patrol officer who retired from the House this year after 10 years as a legislator.
Rep. Greg Forristall of Macedonia faces a challenge from Clint Fichter, the city manager in Avoca, who ran for a county office as a Democrat in 2004.
"One of the reasons you might see this is 2010 was a good year for Republicans, and you have people inspired to get involved and seek office," said Chris Larimer, a political scientist at the University of Northern Iowa. "Just as you saw more activity on the Democratic side in 2006 and 2008, which were good years to be a Democrat."
Robinson, meanwhile, said he has "mixed feelings" on whether the primary challenges are necessarily good for the party.
On one hand, it takes time and money for incumbents to fend off the challengers, both of which could be used to work against Democrats in the general election.
On the other hand, it forces the incumbents to work to keep their seats and consider the opinions of their constituents.
"They should be doing that anyway," Robinson said. "But sometimes they need a push, and a challenge can be that push."