"Lay off my wife."

So says Barack Obama about his controversial spouse, Michelle.

The Democratic candidate for the presidential nomination tends to dismiss any inconvenient fact as a "distraction" and to label every stinging criticism as "divisive." So even if he didn't have a husband's natural desire to defend his wife, he'd still probably denounce criticism of Michelle as beyond the pale.

Obama's comments came in the wake of a Tennessee GOP ad calling new attention to Michelle Obama's remark in February that she'd never been "really proud" of America until the nation embraced her husband's campaign.

"If they think that they're going to try to make Michelle an issue in this campaign, they should be careful," Obama said last week, "because that I find unacceptable, the notion that you start attacking my wife or my family."

Again, the Illinois senator's desire to protect his wife from criticism shows his heart's in the right place. The question is, where is his head?

If he truly finds it "unacceptable" for people to criticize his wife, he might want to rethink sending her out as his chief campaign surrogate, particularly when she has proved to be such a rich source of copy for journalists and barbs for critics.

And just out of curiosity, what does it mean, exactly, when a candidate finds something "unacceptable"? In a democracy, finding criticism unacceptable is a surefire way to drive yourself bonkers. It's like saying you find it unacceptable that bears use the woods for a bathroom. It's going to happen whether you accept it or not.

But the larger issue is whether Mrs. Obama - or any political spouse - is a legitimate subject for scrutiny and, yes, criticism. Historically, this hasn't been much of a problem because most politicians' wives played it safe. Sure, the crusading Eleanor Roosevelt had her bons mots, and Nancy Reagan had her moments in the spotlight, but most first ladies have stuck to ribbon cuttings, scone recipes and Girl Scout jamborees.

That all changed with Hillary Rodham Clinton. In 1992, she and her husband (now her ex-officio campaign manager) insisted that she wasn't the Tammy Wynette type. When her work as a lawyer came up during his campaign, she snapped, "I suppose I could have stayed home and baked cookies and had teas."

Bill Clinton, who himself said that electing him would deliver "two for the price of one," put her in charge of his top domestic priority, health-care reform. And though she failed miserably, she certainly wasn't sitting around baking cookies. Continued...