Erick Erickson points his finger at "elitists":

There are a lot of elitist Republicans who have spent several years telling us Mitt Romney was the only electable Republican. Because the opinion makers and news media these elitists hang out with have concluded Romney will not win, the elitists are in full on panic mode. They conspired to shut out others, tear down others, and prop up Romney with the electability argument. He is now not winning against the second coming of Jimmy Carter.

Friedersdorf notes Erickson's amnesia: