At least, the way our Electoral College works a third party candidate can't win. To back this up you only have to examine the 1992 presidential election. Here's a nifty chart I borrowed from Wikipedia.
In order to win the presidency you must first gain enough electoral votes from the states to add up to 270 votes before the other guys do. Unfortunately this seems quite impossible for a 3rd candidate. Even a popular one like Perot did not have enough electoral votes to even carry one state. In fact all he served to do was to split the anti-Clinton vote between two candidates. States like Tennessee, Georgia, Louisiana, Arkansas, and Missouri, which are commonly red states, went to Clinton in 1992. Does this mean that these states magically became full of Democrats just in 1992 when they are commonly red? Not at all. It means that the people who didn't want Clinton to win in those states were busy being split over two other candidates. Now these states alone, even if removing Perot was enough to carry Ohio, would have not been enough. But if you look at the popular vote what would have happened if the 18.9% of people who voted for Perot had voted for Bush instead? It probably would have made enough of a difference in the blue states to make them red. That would have been roughly 60million for Bush and 45million for Clinton. It makes you wonder how that would have effected the outcome of the electoral vote as typically it reflects the popular vote. A third party candidate does nothing but split the vote. Period. A third person can not get enough electoral votes to carry enough states to equal 270 votes. Even if a third person was poplar enough to carry some states the most they could hope for is prevent anyone from getting 270 votes in which case the House of Representatives would make the final choice. Only then could they hope to win.
So what do you do? You don't like either candidate! Well, did you vote in the primary? For the time being the primary seems to be where you go to vote for who you want to be president and the general election is where you go to vote against who you don't want. And just simply not voting has the same effect as voting third party. If the Republicans who sat home and didn't vote, and the Gary Johnson voters had voted for Romney in 2012 it would have been neck and neck and Romney might have won. Obama would not be president and we'd all be better off. It would seem the two party system and the electoral college go hand in hand. If you don't like your party's candidate the primary is where you go to change that next time. That's where the real fight is. It worked in 1980 and we got 8 years of a great president.
