Health care has been conspicuously absent from the presidential campaign in the last few months. But Barack Obama is trying to change that. He's got the right idea--and, more important, the right message. Mostly.

On Saturday, Obama gave a major health care speech in North Carolina. For the next few days, his surrogates will be fanning out to carry his message to local constituencies and to the media. The campaign is also running new ads, distributing a series of mailers, and organizing local events including a series of "Docs for Barack" gatherings.

The primary focus of the push is on the perils of John McCain's health care plan, by now familiar to readers of this publication and other sites that  feature health care wonkery. The gist is this: McCain's health care plan, which changes the tax treatment of health insurance, would shift more people from employer-based insurance into indivdiual coverage. But individual coverage provides much weaker protection: You get fewer benefits for the money, the benefits themselves are more inconsistent, and the potential for fraud much higher. Plus, of course, people with pre-existing conditions can't get decent coverage at anything resembling affordable prices.

What struck me most about Obama's speeech, though, was the political telegraphing. The question about Obama has never been whether, broadly speaking, he was on the right (er, left) side of the health care debate. He's always been a proponent of using government to make medical care affordable for everybody. Nor was the issue his record. As a state legislator in Illinois, he really was instrumental in passing coverage expansions.

The question, insead, has been his poiltical commitment to the issue. Just how badly did he want universal coverage? How hard would he push? Among the reasons to be skeptical: During the primaries, Obama didn't identify himself with the issue as closely as his two rivals, Hillary Clinton and John Edwards. And in the general election, with issues like rising gas prices and the collapse of Wall Street soaking up so much attention, Obama just hasn't focused on the issue much.

Until now. On Saturday, after Obama explained how he hoped to reduce the cost of medical care, he made clear that simply reducing costs was "not enough"--that it's essential to make sure everybody has insurance. And while he said it was an economic imperative, because the costs of caring for the uninsured imposes a "hidden tax" on everybody else, he also described the presence of 45 million uninsured Americans as "one of the great moral crises of our time."

"This is not who we are," Obama said, "and this is not who we have to be."

Near the end, Obama offerd some rhetoric conspicuously reminsicent of what his rivals were using in the primaries. After describing the story of a Florida woman named Robyn, whose son Devon needed a procedure that his insurance company wouldn't cover, Obama made a vow:

I want to say to Robyn and Devon and everyone like them across America, you have my word that I will never back down, I will never give up, I will never stop fighting until we have fixed our health care system and no family ever has to go through what you’re going through, and my mother went through, and so many people go through every day in this country. That is my promise to you."

(Empahsis mine.)

I'd be lying if I said I liked everything about the way this new health care pitch is shaping up. As Ezra Klein noted on Friday, the first of the four ads, which you can see here, seems unnecessarily defensive. The empahsis was on what Obama wouldn't do, rather than what he would.

The Obama campaign has also chosen to focus on the fact that McCain's plan, if enacted, would raise taxes on some people.

This is a complicated issue I hope to address shortly, in a separate post. But I'm not wild about this argument, in part because changing the tax treatment of health benefits has some merit. McCain would accomplish this in a reckless, ill-conceived way that would actually deprive people of health security--so it's right to call him on it. But, done properly and with some complementary reforms, a cap on the tax exclusion for health benefits makes sense.

In other words, I'd rather Obama not demonize the idea, much as I'd rather he not demonize "government-run health care" (which actually works pretty well in a lot of cases).

But the bigger story here is that Obama is promoting health care. And while second-guessers like me were calling for him to do this a while ago, the timing may actually be perfect. In a week when McCain is trying to distract voters with absurd charges that Obama has been "palling around with terrorists," the health care offensive puts McCain on the defensive. See, for example, this new ad.

The McCain campaign has, in fact, spent much of the past few days trying to answer charges like these, with memos and conference calls. 

Of course, aggressively defining the health care issue now has one more advantage for Obama. It will let him use the waning stages of the campaign to build a mandate for reform. If he wins in November--and, to be clear, I don't assume he will--the time he spends promoting health care reform now will pay political dividends come 2009.

--Jonathan Cohn