In the Iowa caucuses, winning isn’t enough. Mitt Romney narrowly defeated Rick Santorum in the first contest in the Republican presidential race, yet his prospects of capturing the nomination were scarcely improved.

He now faces an opponent, Santorum, who can credibly claim to be an honest-to-God conservative alternative to Romney in what may now be a two-person race. Should the press go along with this, as it’s no doubt inclined to, Romney will have a tougher battle on his hands than he must have expected pre-Iowa.