Dave Weigel at Slate notes the similarity between the GOP primaries last time:
I’m thinking of a Republican primary. It starts with a candidate (John McCain/Mitt Romney) who ran once before, came in second place, and won over the party’s elite class without winning over its base. Other candidates, understandably unwilling to accept this, line up: An under-funded social conservative (Mike Huckabee/Rick Santorum), an elder statesman who’s walked to the altar three times (Rudy Giuliani/Newt Gingrich), a libertarian who wants to bring back the gold standard (Ron Paul/Ron Paul).
The conservative base is displeased. In the year before the primary, it pines for a perfect candidate. At the end of summer, on (September 5/August 13), it gets him: (Fred Thompson/Rick Perry). The dream candidate immediately rises to the top of national polls, but collapses after lazy, distaff debate performances. When the primaries arrive, he’s in single digits and reduced to attacking the front-runners. But in Iowa, he does just well enough to justify staying in the race.
The Republican base looks at the wreckage and shudders. It can never allow this to happen ever again.
And there you have the definition of insanity: doing the same thing over and over and expecting different results.
Rachel Maddow does the video version.