Nate Silver breaks down Super Tuesday:
If you were expecting the kind of dominant candidate who could win North Dakota and Tennessee despite once having governed as a moderate in Massachusetts, you will have been disappointed in Mr. Romney. You would also have been paying very little attention to national politics for the past year. Dominant candidates do not trail people like Herman Cain and Donald Trump in the polls...
If instead you were expecting the kind of candidate who is very likely to win the Republican nomination despite losing North Dakota and Tennessee, you would have found your man.
North Carolina is not Tennessee, but if we'd voted yesterday I'd guess Santorum would have done better here than he did in Massachusetts or Idaho, and also assume a lot of his potential supporters will turn out to vote for the awful Amendment 1 even if he washes out by early May, so the campaign against the amendment had better stay sharp.