Credit Rick Santorum with accepting the obvious: he lost. Despite winning 11 primaries, Mr Santorum was always more of an irritant than a plausible contender for the Republican nomination. He surrenders the field having done a meaningful, though not enormous amount of harm to his side.
Mr Romney is none of those things, however, and with Mr Santorum out of the way, he now can get on with the business of challenging Barack Obama. With the primaries unofficially over, the shape of the fall race is fast emerging. Simply stated, Mr Romney is going to run against the Obama economy while Mr Obama runs against Mr Romney himself.