So, remember a few months ago, when people like me were saying that the third parties are the only hope in America's democracy? Then a bunch of people said that Obama was worlds different from Romney, and that comparing Obama to Bush was lunacy. I have to wonder what happens when those Obama supporters with left-wing sentiments read an article like this.
If D and R are interchangeable what makes you think a third party would be any different?
The problem with two parties is that they collect votes based on ideology not actions. Technically three isn't enough to avoid this but in general use it implies many third parties, such that governing is no longer one painful voice pushed on everyone, but a consensus of the governed.