Gregg Easterbook fears a Bloomberg candidacy:
Carter lost because a third-party vanity candidate, John Anderson, siphoned off liberal voters. The elder Bush lost because a third-party vanity candidate, Ross Perot, siphoned off conservative voters. Plus, in 2000, a third-party vanity candidate, Ralph Nader, threw the election to the younger Bush, away from Al Gore, who prevailed in the popular vote.
That’s three of the last seven presidential elections swung by third-party candidates who were in the race mainly as acts of self-flattery.
That last dig seems unfair to Perot to me. Yes he was a bit of a nutter, but his crusade against debt was what motivated him to get in. But I tend to agree with Steve Kornacki who believes the broader economic climate dwarfs the impact of three candidates:
With or without Perot in '92, Bush would have lost — just as Carter (running under similar condition) would have lost with or without Anderson in 1980. The same goes for Obama next year: A double-dip recession will probably doom him, whether he has one general election opponent or two. Conversely, if the economy continues to improve, there simply won't be room for a major third party candidate; and if a self-funding third party candidate like Bloomberg were to force the issue, it wouldn't be a threat to Obama, since swing voters will happily reelect a president they like if they perceive the economy to be on the rebound. This is why there was no room for an independent candidate when Reagan ran for reelection in 1984, and why Perot was unable to gain traction when he ran again in 1996.