At Thursday's Las Vegas debate, Sen. Hillary Clinton, D-N.Y., regained her footing as Sen. Barack Obama, D-Ill., stumbled.
The specific issues were health care, Social Security, and driver's licenses for illegal immigrants.
But the clarity of the contrasts is what mattered most:
1. Cover Everyone
2. Spare The "Middle Class"
3. Don't Reward Law-Breaking
Obama has offered a health-care plan to make health insurance more affordable.
But the free-rider problem, which Clinton's individual mandate addresses, is a real one.
"Many experts in health care agree that without a mandate, some people would not get coverage," writes the New York Times' Michael Cooper.
Obama has been more explicit than Clinton in proposing a plan to shore up Social Security.
But his call for imposing up to a 12.4 percent tax on all income above $97,500 constitutes a tax increase lower down the income ladder than has been contemplated by either Clinton (in private) or John Edwards (in public).
"I don't believe Mr. Obama is a closet privatizer," Paul Krugman columnizes in the New York Times. "He is, however, someone who keeps insisting that he can transcend the partisanship of our times -- and in this case, that turned him into a sucker."
And even though the Clinton camp recently backtracked on the license issue, it is now Obama who finds himself on the unpopular side of a passionate "eighty-twenty" issue.
Clinton was clearly helped Thursday by the decision of Wolf Blitzer, the debate's moderator, to focus on the candidates' operative positions on driver's licenses rather than on the circuitous route which Clinton had taken in developing her stance.
But Obama compounded the problem posed by his unpopular position by appearing to wiggle away from it for just a moment.
Asked if he supports giving driver's licenses to illegal immigrants, Obama seemed to hedge, saying, "I am not proposing that that's what we do."
After Blitzer said, "This is the kind of question that is sort of available for a 'yes' or 'no' answer," Obama firmed up his answer and explained that he does favor licenses as a public safety measure.
But the damage had been done.
"The unfolding of the question and answer did not play well for the Illinois Senator," wrote the Washington Post's Chris Cillizza.
The dean of the Iowa political press corps was even less forgiving.
Obama's answer was "as nuanced and fuzzy as Clinton's was a couple of weeks ago," wrote the Des Moines Register's David Yepsen.
On Nightline following the debate, ABC's Jake Tapper set up the Obama bite by saying that Clinton's opponents "seemed to have brought with them bags of nuance and explication."
Politico's Roger Simon accused Obama of trying "the same duck-and-cover tactic that Clinton failed at in the last debate." Simon also noted that Obama's answer led to "laughter in the debate hall" . . . "and not the good kind of laughter."
On ABCNews.com, David Chalian wrote that Obama may now find himself having to explain why he supports a "broadly unpopular position among Democrats and Republicans."
The clean-up effort begins:
One day after a debate which was widely given to Clinton, the Obama campaign is pushing back on Social Security.
It is releasing a letter to Clinton from Iowan Tod Bowman in which he asks the former first lady whether she is still considering raising the Social Security tax cap.