It’s a serious plan, one that resembles the law signed in Massachusetts by Mr. Romney, the former governor there. But lack of insurance is only one of the two big problems with health care in this country, and it may well be the smaller problem. Even among the insured, there is an enormous amount of inefficiency today. Some patients get expensive treatments that bring little benefit, while millions of others miss out on basic care, like cholesterol-lowering drugs, that would make a huge difference to them.

Solving that problem will require changing the system so that it rewards good care not just any care. It will mean that Medicare and insurance companies must get tougher about saying no to $10,000 operations that haven’t been proven effective. Mr. Edwards’s white paper on health care includes some of these ideas, but he doesn’t emphasize them on the stump. And this is the sort of change that will require political leadership. Will Mrs. Clinton or Mr. Obama try to provide it?

For that matter, will one of the Republicans? At this point, they are focused on taxes, a make-or-break issue for many Republican primary voters. “We’re facing a gigantic tax increase,” said Michael Boskin, a top Giuliani adviser who, as an aide to George H. W. Bush, unsuccessfully tried to persuade his colleagues to take the 1990-91 recession more seriously.

It’s conceivable that Mr. Romney may go even further than extending the recent tax cuts and propose new ones. His top economic advisers are Mr. Hubbard; Gregory Mankiw, a Harvard professor and former aide to the current President Bush; and John F. Cogan, a Reagan budget official now at Stanford. They like tax cuts.

Mr. McCain, for his part, voted against both of the big Bush tax cuts. He said the first was too big and didn’t do enough to help the middle class, while the second was too expensive in a time of war. But because letting them expire would feel like a tax increase — and because Mr. McCain knows how his primary voters feel about tax increases — he supports them now.

Eventually, though, the Republican candidates will talk about issues besides taxes. To deal with the budget deficit, they will have to come up with ideas for spending cuts. Nothing is a bigger long-term expense than Medicare, which will bring the debate right back to health care.

The truth is that if you put the economic advisers, from both parties, in a room and told them to hammer out solutions to the country’s big economic problems, they would find a lot of common ground. They could agree that doctors and patients need better incentives to choose effective medical care. They would probably hit upon education policies along similar lines, requiring that schools be held more accountable for what their students are, and are not, learning. They might suggest a carbon tax — a favorite idea of Mr. Mankiw — to deal with global warming. And they would shore up Social Security by reducing benefits for high earners, as Mr. Hubbard has suggested.

Not all of these ideas are politically feasible at this point, but presidential campaigns can change what’s feasible. Here’s hoping that this year’s crop of economic advisers has the courage of their convictions.