Of the population of voters who would even consider voting for Ralph Nader, exactly zero would divert their votes from McCain. Nader and his colossal ego will do nothing but drain Obama’s base. The only question is whether Nader’s impact will be:
A) at least as negligible as the libertarians and Transcendental Meditation votes; or
B) annoying like Ron Paul but otherwise not enough to have a meaningful impact; or
C) enough of a draw for “progressives” as as to spoil a critical state or two for the Democrats like Ohio, Pennsylvania, or Florida.
Whether the result is A, B, or C, McCain benefits.
He gets fewer than 100k votes nationwide and makes no impact at all. The guy is just sad. You have to strain to remember a time when he was something other than a sad joke.
If Nader had spent the last 8 years building up a serious 3rd party movement, he would be in perfect position to impact the 2008 election. But since he hasn’t, very few will take him seriously. Perhaps 300,000 pot smokers.