By Gloria Borger
CNN Senior Political Analyst
(CNN) -- In politics, particularly after you've arrived at the White House, the rule of thumb is this: retreat from controversy. When it happens, as it inevitably will, try to back off. Change the subject if you can. And remember, calm is good. Pot-stirring, not so good.
But when President Obama went to Notre Dame to deliver the commencement address over the weekend, he threw the conventional rules away, or at least ignored them.
It would have been easy (some might say, even advisable) to lightly gloss over the obvious elephant in the room: the debate over abortion rights.
After all, there he was at a Catholic university, whose very invitation to the pro-choice president sparked the vitriol of anti-abortion activists -- and the disapproval of those who simply believe that Obama at Notre Dame was a wrong time-wrong place kind of invitation.
It might have turned out that way, in fact, had the president decided to avoid the controversy. But instead, he purposefully stepped into it, elevating the mundane political imbroglio into a national "teachable moment" -- a discourse about the civil way to disagree on an issue that has largely been characterized by its emotional turmoil.
Sure, there was some detour into commencement platitudes about a "search for common ground" and the like, but not much. Instead, Obama waded right in, acknowledging the "controversy surrounding my visit here."
But he did not stop there, although he certainly could have. Instead, he preached his own political gospel from the Notre Dame pulpit.
"Maybe we won't agree on abortion," Obama told the students. "But we can still agree that this heart-wrenching decision for any woman is not made casually. It has both a moral and a spiritual dimension."
And he spoke of working to try to find ways to reduce unwanted pregnancies and to promote adoption -- reasonable political detours around the minefield. But mostly, what the Notre Dame graduates heard was a president -- indeed, a politician -- who had actually pondered the issue beyond the bumper sticker.
This is someone who took down the wording "right-wing ideologues" from his Web site when he ran for the Senate after being challenged on it by an anti-abortion activist. And he's a president who told the students that "the ultimate irony of faith is that it necessarily admits doubt."
Try to put that in a 30-second TV spot.
You can't. And that's precisely why the Republicans -- and some Democrats -- are having so much trouble getting a handle on this president.
He doesn't shy away from this kind of controversy, but chooses to confront it civilly. He makes decisions (eliminating military tribunals), then decides to change his mind (he'll have another version of them) when he's wrong.
He thrills liberals (closing Guantanamo, releasing the so-called "torture memos"), then disappoints (when he decides not to release photos of prisoners in Iraq and Afghanistan allegedly being abused by their American captors). He calls for bipartisanship, yet is happy to pass a budget and economic bailout plans with hardly a GOP vote.
For their part, six out of 10 Americans like Obama, according to our latest CNN/Opinion Research Corp. poll. While nearly half disapprove of the polarizing House Speaker Nancy Pelosi, Obama gets credit for trying to bring change to Washington. She's the old politics; he's the new guy who wants to change things.
In some ways, of course, he's failed. Partisans still bicker; the cavernous ideological divides remain. But when the president decides to stir the pot on abortion, it's because there needs to be a dialogue, and it's clear there's more to come.
More conversation, that is -- and maybe less culture war. As someone once famously said, bring it on.
The opinions expressed in this commentary are solely those of Gloria Borger. Gloria is a senior political analyst for CNN, appearing regularly on CNN's "The Situation Room," "Campbell Brown: No Bias, No Bull," "AC360" and "State of the Union with John King," as well as special event coverage.