Before we start celebrating, however, we have to ask the obvious question. Is this gift a Trojan horse? After all, several of the organizations that sent that letter have in the past been major villains when it comes to health care policy.

I’ve already mentioned AHIP. There’s also the Pharmaceutical Research and Manufacturers of America (PhRMA), the lobbying group that helped push through the Medicare Modernization Act of 2003  a bill that both prevented Medicare from bargaining over drug prices and locked in huge overpayments to private insurers. Indeed, one of the new letter’s signatories is former Representative Billy Tauzin, who shepherded that bill through Congress then immediately left public office to become PhRMA’s lavishly paid president.

The point is that there’s every reason to be cynical about these players’ motives. Remember that what the rest of us call health care costs, they call income.

What’s presumably going on here is that key interest groups have realized that health care reform is going to happen no matter what they do, and that aligning themselves with the Party of No will just deny them a seat at the table. (Republicans, after all, still denounce research into which medical procedures are effective and which are not as a dastardly plot to deprive Americans of their freedom to choose.)

I would strongly urge the Obama administration to hang tough in the bargaining ahead. In particular, AHIP will surely try to use the good will created by its stance on cost control to kill an important part of health reform: giving Americans the choice of buying into a public insurance plan as an alternative to private insurers. The administration should not give in on this point.

But let me not be too negative. The fact that the medical-industrial complex is trying to shape health care reform rather than block it is a tremendously good omen. It looks as if America may finally get what every other advanced country already has: a system that guarantees essential health care to all its citizens.

And serious cost control would change everything, not just for health care, but for America’s fiscal future. As Mr. Orszag has emphasized, rising health care costs are the main reason long-run budget projections look so grim. Slow the rate at which those costs rise, and the future will look far brighter.

I still won’t count my health care chickens until they’re hatched. But this is some of the best policy news I’ve heard in a long time.