By Joseph J. Schatz, CQ Staff

At a Republican convention that appears full of Sarah Palin fans, at least one prominent conservative doubts out loud that the Alaska governor is qualified to be John McCain ’s running mate.

But that lonely skeptic is not a Republican anymore.

Former Rep. Bob Barr of Georgia, who accepted the Libertarian Party’s presidential nomination in May, is in St. Paul making the rounds with the media and chatting with old friends like former House Majority Leader Tom DeLay of Texas and former House Republican Conference Chairman J.C. Watts of Oklahoma.

Barr, 59, is perhaps best known for his role in the House impeachment of former President Bill Clinton in 1998. After serving in the House from 1995 to 2003, Barr left the GOP in 2006.

Barr said reports of a “cursory vetting process” for Palin “raise questions about the way McCain reached his decision.”

Noting that McCain is 72, Barr said he wonders whether Palin “has the experience – not just the superficial experience – to really size up” foreign policy issues.

Barr pointed to what he termed President Bush’s foreign policy inexperience when he took office, saying that Bush had a “very serious misinterpretation of Vladimir Putin when he first met him.” Bush famously said that he was able to “get a sense of his soul” when he met Russia’s then-president, who is now prime minister.

“It’s not something you gain by serving as mayor for a couple of years, or as governor for a couple of years,” Barr said.

Not that foreign policy experience is a strong suit for Barr’s own running mate, Wayne Allyn Root, a sports gambling handicapper, author, TV producer and small-business owner.

While Barr registers in the low single digits in national polls, his candidacy could potentially be a factor in some states if the fall contest between McCain and Democratic nominee Barack Obama is tight. Barr said he expects to be on the ballot every state, noting that he currently has lawsuits pending in Oklahoma and West Virginia with an aim of running in those states.