If Barack Obama is elected president of the United States on Nov. 4 - a prospect that is beginning to seem likely now - it may turn out that he closed the deal with a simple answer to a not-so-simple question posed by Tom Brokaw in the second presidential debate: "Is health care in America a privilege, a right or a responsibility?" This is familiar territory for Democrats. The question was framed many years ago by Senator Ted Kennedy, who must have been smiling up on Cape Cod. "Health care should be a right, not a privilege," Kennedy would say, so often that it became a cliché. But it was unfamiliar turf for John McCain, who responded by wandering through his answer - halfheartedly, it seemed - saying it would be his responsibility as President to provide affordable health care to those who needed it.

    Obama began his response with a simple declarative sentence: "I believe that health care is a right for every American." The rest of his answer could be used as a template for how to deal with a complex issue in a town-hall debate. He began with a personal story: his mother, dying of cancer at age 53, having to fight her insurance company, trying to prove that her disease had not been a pre-existing condition. He broadened that into a general proposition about the proper role of government: "It is absolutely true that I think it is important for government to crack down on insurance companies that are cheating their customers." And finally, he transformed the issue into a metaphor for the entire campaign: "That is a fundamental difference that I have with Senator McCain. He believes in deregulation in every circumstance. That's what we've been going through for the last eight years. It hasn't worked, and we need fundamental change."

    Obama was right. The health-care issue illustrates not only the philosophical differences between the two candidates but also the political difficulties McCain has been having in this election. Obama's gamble is that the public - worried at the beginning of the campaign, terrified now - is ready for greater government support and regulation of the health-insurance system. That assumption has always been a sure loser in American politics. Republicans have perpetually and successfully waved the bloody flag of "socialized medicine." But the employer-provided-health-care system is fraying, costs to average families are rising, and almost everyone has a friend with a horror story. McCain's plan is a half-baked vestige of Reagan-era ideology: it tilts the incentives away from employer-provided health insurance and assumes that people will act in their enlightened self-interest if they are thrust out into a free market. That's absolutely true when it comes to buying refrigerators. But health insurance is complicated and scary; most people don't have the time or expertise necessary to make wise choices. They rely on their employers to make sure they're getting a good deal - and to fight for them if the insurance companies try to cheat them. And with many employers slouching away from that responsibility, the public seems ready to turn to the government for protection. In a collapsing economy, government regulation - forcing insurers to cover everyone at reasonable rates - sounds more comforting than stultifying.

    The desire for more government activism is true across the board. All of a sudden, government-provided infrastructure programs - and that's what most of McCain's despised "earmarks" are - don't sound like such a waste of money, especially if they are married to alternative energy sources and conservation (which is why Obama talks constantly about "retrofitting" buildings to conserve energy). All of a sudden, boring bureaucracies like the Securities and Exchange Commission, which have been undermined and underfunded by Republicans, become a crucial bulwark against the rampaging free-market anarchists on Wall Street. This is, as Obama says, a fundamental change - but not a radical one. It is a modulation, a move to preserve the free market by controlling its excesses.

    But McCain's candidacy has other problems. He simply isn't as skillful a communicator as Obama is. The difference between them was made clear in the second question of the debate - a fellow named Oliver Clark wanted to know how the Wall Street bailout would help his friends who were in trouble. McCain's answer was all over the place and obscure in a classic Washington way; he detoured into blaming Fannie Mae and Freddy Mac and pointing his finger at Obama and "his cronies" for supporting those two incomprehensible institutions. Obama, by contrast, brought the bailout home in simple language: "Well, Oliver, first, let me tell you what's in the rescue package for you. Right now, the credit markets are frozen up, and what that means, as a practical matter, is that small businesses and some large businesses just can't get loans. If they can't get a loan, that means that they can't make payroll. If they can't make payroll, then they may end up having to shut their doors and lay people off."

    I don't think McCain has answered a single question with that sort of clarity in these debates. He answers with oblique gestures - raising totems like General Petraeus and Senator Joe Lieberman as proof of his bona fides - or attacks on targets (like "liberalism") whose relevance has evaporated during the past eight years. Even when it comes to national security, his alleged area of expertise, McCain has difficulty explaining himself. His waffling about whether to cross the border into Pakistan for targeted strikes against al-Qaeda leaders was both foolish and incomprehensible: if the Pakistanis are our allies, as he insisted, why are they protecting the terrorists? Obama, by contrast, answered with simple declarative sentences: "We will kill bin Laden. We will crush al-Qaeda. That has to be our biggest national-security priority."

    Obama's had another advantage in these debates, one that is difficult to quantify but very real: he simply seems more comfortable, and confident, than McCain. Part of this is, sadly, attributable to the physical awkwardness imposed by McCain's war wounds and his bouts with cancer - the restricted arm movements; the scarred, clenched jaw. But there is also a pent-up anger to McCain. He seems to be concentrating so hard on trying to stay calm that he doesn't have much energy left over to answer questions in a free and creative way. He is not the sort of person, in the end, that you want to invite into your living room for a four-to-eight-year stay.

    Barack Obama is. We are witnessing something remarkable here: Obama's race is receding as he becomes more familiar. His steadiness has trumped his skin color; he is being judged on the content of his character. But there is a real challenge - and opportunity - inherent in his success. Obama has taken some inspired risks in this campaign. His willingness to propose more governmental control of the health-care market is a prime example. But he has also been very cautious, a typical politician in many ways. The most obvious is in his resolute unwillingness to deliver bad news or make any significant demands on the public. Neither he nor McCain had anything but platitudes to offer when asked what sacrifices they would ask of the American people. Worse, when Brokaw asked if he thought the economy was going to get worse before it gets better, Obama flatly said, "No. I'm confident about the economy."

    That was, no doubt, the politic answer. But not the correct one. Obama was underestimating the public's capacity to hear the truth - which is odd, since the national desire for substance, the unwillingness to be diverted by "lipstick on a pig" trivialities, has been so striking in this campaign. Everyone knows this recession is going to hurt, that there will be a price for our profligacy and that some hard shoveling will be necessary to get out of this hole. Indeed, that knowledge is what has made Obama's success possible. But if he wants to do more than merely succeed, if he wants to govern successfully, he is going to have to trust the people as much as they are beginning to trust him. After years of happy talk from politicians, that is the change we really need.