The spoiler?

David Weigel looks at the number three guy in the race for the presidency:

Never in the history of the Libertarian Party has an idea been executed so smoothly as the nomination of Bob Barr, a former Republican congressman — and former drug warrior — from Georgia. True, it took six ballots at the party’s national convention in Denver to nominate the man. True, the weekend before that vote was a marathon of rumors, threats, and twisted arms, with younger, more radical party members pitted against an old guard that included party founder David Nolan. But the ruckus culminated in the nomination of the most well-known and politically astute presidential candidate in party history. Rep. Ron Paul (R-Texas), the only other former congressman to run for president on the Libertarian ticket (in 1988), had already made 2008 a banner year for libertarian politics by launching a limited-government revolt in the Republican primaries. The question: whether Barr is poised to continue what Paul began.

Barr's campaign — and the possibility of a revitalized national Libertarian Party — will likely have more of an immediate electoral impact than Paul's did. The Republican Party, after all, is teeming with antibodies that have been able to fight off the diminishing libertarian virus within. Unless lightning struck, the heavens opened, and he stumbled upon the Ark of the Covenant, Paul was never going to win the GOP nomination. It wouldn't take much, though, for Barr's popularity to force John McCain to campaign in states he thought he had wrapped up, or even to swing one of those states into the Democratic column. The Libertarian Party has its greatest chance to affect a presidential election in 28 years.

Of course, should that happen to McCain's detriment, the few remaining libertarian-leaning Republicans should expect show trials (at the minimum) or death threats from their less principled co-religionists.