Over on Marc Ambinder's blog at The Atlantic is a memo from a guy who worked for Perot in 1992 and wants to work with a Bob Barr third-party Libertarian run. He points out that Perot got 19% of the vote in 1992.

Conventional wisdom says a serious third-party push from a Bob Barr-type would hurt McCain, and on paper it's true. But what concerns me about the prospect is that it would handicap the Democrat (presumably Obama) who wins the White House in November.

Bill Clinton had a pretty good presidency. Much of the problems he had were the result of the confluence of partisan Republican gameplaying, a problematic media environment, and his own personal shortcomings. But I believe the fact that Clinton never had won an outright majority of the electorate also played into the attacks on him. We can argue whether Perot's run in 1992 may have thrown the election from Bush to Clinton. But I don't think it is arguable that Clinton's lack of an outright majority of the vote helped make him vulnerable. And I would fear that outcome this time around.

I believe Obama's capable of winning a real majority. I worry that in three-way race, however, he'd wind up winning with only a plurality--and that would give the opposing GOP cover to be obstructionist.

(This is not an argument against BHO; I think this scenario is just as possible--perhaps even more so--if Hillary Clinton were the Democratic nominee.)

How risky do you think that prospect might be?