McCain's credit is "not realistic in terms of the amount," said Christine Ferguson, a professor at George Washington University and a former senior health policy advisor to Republican lawmakers at the federal and state levels. "McCain would have to step up a little more."
How McCain's plan would affect people who have job-based coverage is a matter of dispute. His advisors say the effect would be negligible, since the credit would be enough to wipe out the new tax liability for most employees. But some workers would end up paying higher taxes, especially well-paid ones with comprehensive coverage.
Independent analysts say that over time, McCain's tax credit would not keep up with healthcare inflation. Younger, healthier workers would be tempted to buy low-cost coverage on their own. That might help squeeze wasteful spending out of the healthcare system, but it could leave employers stuck with older and sicker workers, and those companies might stop providing benefits.
Then everybody would be pitched into an individual market that traditionally has been unforgiving for people with health problems. For example, cancer survivors often find they cannot get coverage as individuals or, if they are offered a policy, the price is out of reach.
"McCain is talking about Wild West competition where there are no limits," said economist Len Nichols, who directs the health policy program at the New America Foundation and served as an advisor in the Clinton White House.
But McCain, who has been treated for melanoma, says he recognizes that there is a flaw when it comes to coverage in today's individual market, and he would work with states to craft effective protections for people in poor health, such as special risk pools and basic standards for insurers.
And his aides predict that membership organizations such as AARP -- the seniors lobby -- and labor unions and religious denominations would sponsor health insurance, creating new pools and taking the place of employers. Then, they say, workers could switch jobs without fear of losing coverage.
In contrast to McCain, Clinton and Obama would not make any major changes in the tax treatment of healthcare benefits.
Instead, they would concentrate on closing gaps in the insurance system. Both envision a shared responsibility among employers, individuals and government -- although the public role would become markedly stronger.
