"If you're a healthy person in a low-cost area, this is a pretty good deal," said Len Nichols, a healthcare economist who directs the health policy program at the New America Foundation. "If you're a healthy person in a high-cost area, not so much. If you're an unhealthy person in a high-cost area, good luck."

To make sure these older and sicker people can afford insurance, McCain has proposed a pool funded by the states and federal government that the campaign says would provide them access to care at a "reasonable" rate. Critics say it would be either far more expensive than the $15 billion to $20 billion McCain says it would cost, or that premiums would have to be high.

Barack Obama's plan would not result in the same geographical disparities. The Obama plan would preserve the tax breaks on employer contributions to health insurance, so the value of those exemptions would remain directly related to the cost of insurance. Obama would provide tax credits for people who can't afford the full price of health insurance; those credits would also be directly related to a person's income and the price of the plan, said Neera Tanden, director of policy for the Obama campaign. LINK