Great summary of the last several weeks of the Republican campaign.
The "too long; didn't read" or tl;dr version of the article is that Romney has alienated both independents and the Republican base, meaning that he likely can only win a general election if Europe or Iran fuck things up for Obama. He might even lose the nomination if he is unable to destroy Santorum in the same way he destroyed Gingrich. If Santorum wins the nomination, his mostly-inevitable loss to Obama would cause the GOP to move in a more moderate direction in 2016. If Romney is the standard-bearer who loses in November, it would drive the party into the waiting arms of 2016 nominee Sarah Palin.