Here is an article from Bill Kauffman that addresses the two party system and third parties. It is from The American Conservative:
In his memoir If You Don’t Weaken (1940), Oscar Ameringer, witty and humane radical from the erstwhile hotbed of American socialism, Oklahoma (it really was!), professed a “rule of never voting for a presidential candidate who had the slightest chance of election. The ballot is too precious lightly to be thrown away on candidates selected and financed by the ‘angels’ and archangels of the two historic old parties which have managed my adopted country into the condition it is in today.”
Oscar’s statute remains sound. We are facing in 2012 the worst Democrat-Republican twosome since, uh, 2008? 2004? 2000? I detect a pattern.
A state’s electoral votes have never been decided by a single popular vote, so as history is our guide your vote for president does not matter…