Debate Question for Obama: Why has Bipartisanship Failed?

One of the key campaign policies of then Senator Obama in the 2008 was a commitmment to Bipartisanship and Unity. 4 Years later and Bipartisanship is a failure and a skit on SNL. What happened and why?

Here are three views on what happened.
New York Magazine – Why Did Obama’s Bipartisanship Fail?
The Guardian – Bipartisanship is not going to work
TheModerateVoice – Is Obama hopelessly naive?
TheMaddowBlog – Bipartisanship never stood a chance

I searched on conservative magazines New Republic, The Weekly Standard and Taki’s Magazine and there were no relevant articles on “bipartisan” or “bipartisanship”.