When Michelle Obama hit Minnesota Wednesday afternoon, acting as First Surrogate for her husband, she lavished her attention and smiles on a couple of dozen students and staffers at the Hope Commiunity in south Minneapolis. She chatted about community organizing, empowerment, that kind of thing, for more than an hour.

But no, her spokeswoman said, no time to take questions from the gaggle of journalists standing by and watching the photo op. A shame, in a way, because she can be candid to a fault, like the time recently when she said Hillary Clinton was a polarizing figure and questioned the so-called inevitability of her nomination. “Sometimes we wear the same suit even if it’s got holes in it,” she said. “We need a new suit, not just a new tie or new pants.”

Typical self-centered journalist quibble, right? Not exactly, because it brought to mind the hermetic bubbles that both Barack Obama and Clinton have sealed themselves in for months on the campaign trail, a phenomenon examined this week by the Washington Post’s Ruth Marcus.

Would a little give-and-take on the campaign trail be such a terrible thing? Wouldn’t it be nice to hear the candidates unlimber and expand beyond the 30-second sound bite? (Which, ironically enough, Michelle Obama mocked during her Minneapolis visit.)