Former Rep. Bob Barr, famous in part for having played a key role in former President Bill Clinton's impeachment, has officially announced his plans to run for the Libertarian Party's presidential nomination.

Barr left the Republican Party in 2006. When I interviewed him last year, he said he'd made that decision in part because of his differences with the Bush administration on civil liberties. The Libertarian Party, Barr said, "is the only [party] that is true to my core philosophy of working to minimize government power and maximize individual liberty."

Barr isn't guaranteed the nomination, which will be voted on at a party convention later this month. According to the convention Web site, 14 other candidates -- including former Sen. Mike Gravel, who has also been running for the Democratic nomination -- will be vying for the nod.

The party says it has ballot access in 28 states already, and Barr would obviously bring a little more name recognition to it. Most observers have seen a potential Barr run as bad news for presumptive Republican nominee John McCain. In 2004, the Libertarian candidate finished fourth, with less than 1 percent of the vote.

In other Libertarian-related news, supporters of Rep. Ron Paul's presidential campaign are still at it. The Los Angeles Times' Top of the Ticket blog reports that "largely under the radar of most people, the forces of Rep. Ron Paul have been organizing across the country to stage an embarrassing public revolt against Sen. John McCain when Republicans gather for their national convention in Minnesota at the beginning of September."