Former Rep. Bob Barr announced today that he will seek the Libertarian presidential nomination, a move that could raise concern among Republicans nervous about anything that might siphon voters from John McCain this fall.

Barr, who became nationally known as one of the lead House members in President Clinton’s impeachment, is enough of a name to potentially attract disgruntled conservatives. “I've heard from Americans from all walks of life,” Barr said in announcing his run. “They want a choice. They believe that America has more and better to offer than what the current political situation is serving up to us."

In order to succeed, Barr will have to win the party’s nomination at the national convention which begins on May 22. Driving concerns among the GOP is Ron Paul, whose bid for the Republican nomination has attracted a vocal and dedicated following. Paul was the Libertarian candidate for president in 1988 and, while he has said he won’t seek to run on a third party ticket, any credible conservative could prove problematic. Barr lost his bid for re-election in 2002 after two GOP districts were thrown together in redistricting and later publicly announced he was leaving the Republican Party.