According to Janice Shaw Crouse's column The Pushy Pundits Forced Romney Out, he (and others) did.

Pardon my sudden ineloquence, but HUH? Romney lost because many of America's most highly respected conservative voices supported him? I am a fairly frequent reader of Crouse's column, and I mean no disrepect, but seriously, does this strike anyone as logical?

Crouse states "They forgot all about their role as analysts and commentators and became advocates". Since when has Rush Limbaugh pretended to be anything less than an ardent advocate of conservatism. By what definition is advocate an inappropriate role for a commentator.

But according to Crouse, its the pundits' fault Romney lost because they promoted him too ardently. So, it wasn't because McCain is a media darling who's fawned over in the press? And it wasn't because McCain was voted for by many who were not self-identified as conservatives, or in many cases, even Republicans? And it wasn't because thanks to years of "big-tent" recruitment, the Republican party is simply not as conservative as once it was?

According to Crouse, apparently not.