If Romney is the eventual Republican nominee, he will have to return to Michigan clearly branded as the guy who was willing to let the auto industry die. If Santorum is the nominee, he'll be the Catholic candidate who couldn't even carry the majority of Catholic Republicans in the state.
Romney ended the Michigan campaign as the patrician whose buddies are the owners of NASCAR teams. Santorum is the religious firebrand who picked a fight with John F. Kennedy over separation of church and state. The result? Neither of the two did themselves a favor in Michigan.
Romney had to fight ugly and spend a fortune to barely prevail in his native state, pushing his negative ratings ever higher. Santorum blew a chance to beat Romney on his home turf by veering off into the weirder realms of social conservatism. That gave him a boost in rural areas but dampened his appeal in the places where most people live, the cities and the suburbs.
Sure, both candidates can claim some sort of positive result in Tuesday's vote. Romney notched another win, while Santorum came surprisingly close. But, at the end of the day, the president now holds double-digit leads over both GOP contenders in Michigan.
That's especially damaging to Romney, who should have been able to count on at least a decent shot at taking the state in November, given his deep roots there. Obama still has many things to worry about in the general-election campaign, but winning Michigan is not one of them.