“Rick Santorum was a sitting senator who, in re-election, lost by 19 points,” Donald Trump, a Mitt Romney supporter, said recently. “Then he goes out and says, ‘Oh, OK, I just lost by the biggest margin in history, now I’m going to run for president.’ Tell me, how does that work?”

Trump exaggerated only slightly; Santorum actually lost by 18 points. But there’s no doubt the most glaring weakness in the case for Santorum’s electability is that 2006 re-election loss. After two terms in the Senate, the voters of Pennsylvania simply threw Santorum out on his ear.