It's not certain that Barr is going to win the Libertarian party's nomination, for which he'll be competing with Mike Gravel (who won't win it) and a number of Libertarian-party insiders. It's also not completely out of the question, I guess, that Ron Paul could enter the running. But if he does, where might Barr have the biggest impact?
Below, I've listed the leading states by percentage of the general election vote that went for Michael Badnarik, the Libertarian candidate in 2004.
2004 Libertarian Party Vote Share
I'll take "states that begin with the letter 'I'" for $200, Alex! Actually, that list is a little weird. I don't think that Indiana has ever really been thought of as a third-party stronghold, for instance. But one thing we need to contend with here is that some people just want to vote for a third-party ... and they're indifferent about which third party they vote for. In Indiana, there were only a couple of third parties on the ballot, so Badnarnik might have picked up a lot of the generic anti-establishment/protest vote. It might be more instructive to look at the total third-party vote in 2004.
2004 Third Party Vote Share (Libertarian vote in parenthesis)
Alaska 3.42% (0.59%)That's a little closer to what I was expecting to see, with a concentration of states in the Interior West. If the American Spectator is right that Barr would drain more votes from McCain than Obama, Alaska and Montana bear watching. And although it hasn't recently had a heavy third-party vote, so might Georgia. If Barr could peel the votes of some culturally conservative whites from McCain in Georgia, who might mistake him for one of their own, Obama might have a path to victory on the strength of the black vote and upscale whites in suburban Atlanta.
Utah 2.47% (not on ballot)
Montana 2.37% (0.38%)
Vermont 2.26% (0.35%)
Wyoming 2.06% (0.42%)
Rhode Island 1.91% (not on ballot)
Maine 1.85% (0.27%)
Connecticut 1.74% (not on ballot)
Nevada 1.65% (not on ballot)
South Dakota 1.65% (0.25%)
UPDATE: More good background on this from the Atlanta-Jorunal Constitution. Barr doesn't seem to care if he plays the role of spoiler.