Obama wants more people to have health insurance. He would require insurance for children, create new options for uninsured adults, and reduce price discrimination against people with health problems.

McCain wants to make insurance more affordable. He would weaken incentives for employer-sponsored insurance - the value of benefits would be taxed as income - while giving people tax credits to help them buy insurance on their own.

But don't expect the election to hinge on health care, political and health-care experts said last week. The Wall Street debacle has grabbed the spotlight for the foreseeable future. More important, it's grabbing billions of dollars, and that likely will constrain reform efforts by either candidate once the election is over.

"The top three issues in the election are the economy, the economy and the economy," said David L. Cohen, a Comcast executive who chairs the board that governs the University of Pennsylvania Health System and who was a top aide to Gov. Rendell when he was Philadelphia's mayor.

"I think everything is past tense now," said Joseph Antos, a health-policy expert with the American Enterprise Institute who has critiqued Obama's proposal. "I don't think any of this is going to happen."

Nonetheless, Jay Khosla, a McCain health-policy adviser, said last week that "health-care reform is going to be a very important priority for McCain."

Obama, whose campaign did not respond to a request for information last week, said he might have to delay some domestic initiatives.

Cohen said he believed health care would continue to resonate with voters. "There's nothing that scares people more," he said, "than losing their health insurance."

And everyone agrees the problems are not going away. Forty-six million people in this country lack insurance, and costs are rising for the people who have it. The Henry J. Kaiser Family Foundation said last week that the average family plan now costs $12,680, up 5 percent from last year.

In Quinnipiac University polling earlier this month in four battleground states, 7 percent to 11 percent of voters listed health as the single most important issue in the election. (More than half chose the economy.) "As you get closer to the election, the economy and national security always become the issue," said Peter Brown, assistant director of Quinnipiac's polling institute. "That's just the way it is."

Political challenges aside, the plans reveal important differences in philosophy.

Obama would expand government coverage by creating a Medicare-like option that younger people could join. He also would make it easier for individuals and small employers to buy insurance through bigger groups. All children would have insurance. He would require greater oversight of insurers, prohibiting them from charging more to people who have health problems. He also would make employers above a certain size provide health insurance or pay an unspecified tax. His campaign estimates the cost of his plan at up to $65 billion a year.

McCain takes a more market-centered approach. He would do away with the tax advantage of having employer-sponsored insurance, substituting tax credits of up to $2,500 for individuals and $5,000 for family plans. The subsidies would make it easier for people to afford buying their own private insurance, which would allow them to keep coverage when they change jobs. Policies could be sold across state lines. There would be no effort to prohibit discrimination against people with a history of illness, so young, healthy people likely would pay less. McCain has a subsidized option for the sick people private insurers don't want. He does not put a price tag on his plan.

Both senators say they'll save money by encouraging greater use of information technology and better management of care, savings that health experts say are likely to be lower than the campaigns estimate.

Health experts say cost likely will be Obama's biggest obstacle, especially in light of the Wall Street mess.

Antos says small businesses in particular might choose to pay Obama's tax rather than buy insurance for employees. The extra cost could lead to lower wages or fewer jobs. And, he said, the plan calls for generous health benefits, which could drive up overall costs.

The Urban Institute, which analyzed both plans, said Obama's would cover about two-thirds of the uninsured, while McCain's would have little effect.

Critics of the McCain approach say it would weaken employer-sponsored insurance without giving low-paid people enough money to buy health plans on their own. Thomas Buchmueller, a health economist at the University of Michigan, estimates that 20 million people would lose work-provided insurance, a number the McCain plan disputes. McCain would not require employers who drop coverage to give workers higher pay instead, though economists think competition for employees would keep pay up. The size of McCain's tax credit is indexed to overall inflation, not the price of health care, which has been rising faster.

McCain's plan would throw workers, who benefit now from their employers' ability to negotiate lower group rates, into the more costly individual health market.

"The individual market is in many ways the worst part of the American health-care system," said Jonathan Oberlander, a University of North Carolina political scientist and health-care expert who analyzed the two plans for the New England Journal of Medicine. "They are building on the worst part of the American health-care system without reforming it."

Antos says neither plan does enough to address rising health costs. Americans have a sense of "entitlement" about their health care and have been unwilling to accept limits. "We have to realize that there are resource constraints in the real world," he said.