It's all very logical, my friends, it's called MATHEMATICS.
Let's simplify it for you: this country has a 2 party system, at this point in our history. That might change, some time in the future, but I sincerely doubt it. A 3rd party candidate has as much a chance in hell of winning the U. S. Presidency, today, as Hugo Chavez becoming a capitalist and declaring his undying love for George W. Bush. It will never happen. Sorry. So, given that, there are only 2 party candidates (the Democratic and Republican) vying for the top dog position that have any hope of winning this election in November. The only 2 viable candidates to choose from are Barrack "Hussein" Obama and John Sidney McCain, III.
If there are only 2 VIABLE candidates, there will be votes destined for Obama and votes destined for McCain. ANY vote NOT for McCain is a vote for Obama and this is why:
Say you have 20 voters- 10 are registered Democrats, and 10 are registered Republicans. The 10 Democrats decide to support Obama, because well, he's a Democrat and they are party loyalists. Obama gets those 10 votes! Now we have the Republicans, some of whom are pissing and moaning about how McCain isn't conservative enough for them, so 2 of those decide, hmmm, we're just going to punish the dang 'ol Republican Party and vote for Bob Barr (or Chuck Baldwin). 1 decides to not vote at all. 1 is an Obamacon, who has been duped into believing all of Obama's lying campaign rhetoric, and decides to vote for Obama. So McCain gets only 6 votes, and Obama wins.
Those 4 non-McCain votes got Obama elected, how is that not a vote for Obama!!