As birtherism resurfaces in the GOP presidential primary, Haley Barbour is the latest to fret the party's damaging its image

Top Republicans are increasingly worried the party is shooting itself in the foot.

The latest is Mississippi Gov. Haley Barbour, who told reporters Tuesday that it's "not good for the Republicans" when presidential candidates bring up issues like President Obama's birth certificate.

"Look, if this election is about Barack Obama's policies and the results of those policies, Barack Obama's going to lose," Barbour said. "Any other issue that gets injected into the campaign is not good for the Republicans."

Barbour was responding to a question about Texas Gov. Rick Perry's decision to stoke the issue of Obama's birthplace. In an interview published over the weekend, Perry said he didn't "have a definitive answer" about where the president's was really born, and on Tuesday he told The New York Times he got a kick out of keeping the issue alive: "It's fun to poke him a little bit."

But Barbour, answering questions after speaking at the National Press Club, said the candidates are hurting their chances if they veer into sideshow territory.

"Republicans should want this election to be what American presidential elections have always been: a referendum on the incumbent's record," he said. "Barack Obama cannot win a second term running on his record -- zero chance. So for anybody to talk about anything else is off subject."