Whatever your perspective on how likely Mitt Romney was to lose the Republican nomination race prior to Tuesday evening, it should be acknowledged that he had about the worst results conceivable. In Minnesota, a state which Mr. Romney carried easily in 2008, he has so far failed to win a single county — and got just 17 percent of the vote. That put him 27 points behind Rick Santorum, and 10 points behind Ron Paul, who finished in second. Missouri is a less important result since its beauty contest primary did not count for delegate selection and since turnout was...