So what went wrong with Santorum?

[memphis]

Santorum's biggest problem was Newt Gingrich.

^^^^^^^^^^
The math isn't that complicated.

[memphis]

He was never supposed to be a serious candidate anyway. He just got lucky with the way the flavor of the week pattern was going and that so many were so anti-Romney. So nothing went "wrong" with him, his success itself was the fluke.

The important part is that a majority of Republicans consistently refused to support Romney, even if it meant running from one joke candidate to the next. He can't rally his party, much less the nation.