"Our job is to make it affordable and available and not set government mandates and big government programs," McCain said at a forum sponsored by AARP, the nation's largest advocate for seniors. "If you like that system I would urge you to go to Canada or England."
Huckabee, the former Arkansas governor who has made his personal bout with diabetes and obesity a centerpiece of his campaign, said lowering medical costs would solve the nation's health care problems, not universal health care.
"I don't trust the government with my health, and I don't trust insurance companies with my health," he said. "I trust me."
The forum featured a more relaxed town hall-style, with Huckabee and McCain strolling to the stage in the ornate old Orpheum Theater to address about 750 people.
A moderator asked questions about health care and financial security. Both stuck largely to standard campaign themes, with McCain repeating his call for a bipartisan commission to research ways to solve the crisis of Social Security.
"The dirty secret in America today is that Medicare and Social Security are going broke," McCain said. "We owe them the responsibility to make the hard choices and not hand it off to future generations."
Huckabee pointed to his experience as governor dealing with issues like long-term care.
Both candidates said they would push for tax incentives to make it easier for people to buy health insurance.
Huckabee argued that 80 percent of the nation's health care spending goes to treat chronic diseases, and that more attention should be paid to preventing illnesses.
"Everything becomes easier when we become a healthier country," he said.
The forum was the second in Iowa this year sponsored by AARP, one of the most important groups in Iowa politics. There are 390,000 AARP members in Iowa, and statistics show that more than 60 percent of those who showed up for Democratic caucuses in 2000 and 2004 were older than 50, the minimum age for membership.
The AARP sponsored a debate last month in Davenport that drew all but one of the major Democratic candidates. Only Huckabee and McCain agreed to appear for Thursday's GOP forum. Other candidates -, and skipped the meeting, citing scheduling conflicts and the crush of scheduled debates.