“It’s morning in America.”

This may be the key ingredient that Romney found in Michigan. Reaganesque in his good looks, Romney also shares the Gipper’s crucial optimism. And as Michigan exposed in McCain’s cranky “your jobs aren’t coming back” rhetoric, it gives Romney a human element to contrast with McCain’s authenticity.

Suddenly, McCain sounds less like a straight-talker than an old curmudgeon. Next to Romney’s sunniness, it won’t wear well. The electorate likes glass-half-full guys.

You hear it in the two candidates approach to climate change. McCain sounds like Al Gore. Like Gore in “Earth in the Balance,” McCain sees an America with limits. It is a country that needs to be reigned in; cured of its “dysfunctions.”

Romney, on the other hand, sees nothing but U.S. potential. He’s all about wide-open horizons, not cramped federal mandates. It’s there when you meet him. It’s in his DNA. And, not surprisingly, he dismisses climate change as a serious issue.