BOSTON, Nov. 20 — As the Democratic presidential candidates debate whether Americans should be forced to obtain health insurance, the people of Massachusetts are living the dilemma in real time.
A year after Massachusetts became the only state to require that individuals have health coverage, residents face deadlines to sign up or lose their personal tax exemption, worth $219 on next year’s state income tax returns. More than 200,000 previously uninsured residents have enrolled, but state officials estimate that at least that number, and perhaps twice as many, have not.
Those managing the enrollment effort say it has exceeded expectations. In particular, state-subsidized insurance packages offered to low-income residents have been so popular that the program’s spending may exceed its budget by nearly $150 million.
But the reluctance of so many to enroll, along with the possible exemption of 60,000 residents who cannot afford premiums, has raised questions about whether even a mandate can guarantee truly universal coverage.
Additional concerns have been generated by projections that the state’s insurers plan to raise rates 10 percent to 12 percent next year, twice this year’s national average. That would undercut the plan’s secondary goal of slowing the increase in health costs.
“We’re going to be very aggressive in trying to get those numbers down to single digits,” said Jon M. Kingsdale, executive director of the Commonwealth Health Insurance Connector Authority, the agency that markets the subsidized insurance policies. “If we continue with double-digit inflation, I don’t think health reform is sustainable.”
The state’s experience should be instructive to the presidential campaigns, and to officials in California, where Gov. Arnold Schwarzenegger, a Republican, has proposed a similar plan. Democratic leaders there initially rejected an individual mandate because labor unions argued that workers might not be able to afford coverage. They have recently reversed course, but have yet to agree with Mr. Schwarzenegger on how to finance the plan.
Each of the three leading contenders for the Democratic presidential nomination has pledged to achieve universal health coverage, which polls show to be a priority for party voters. But as the candidates seek to differentiate themselves, a rift has emerged over whether it is possible to insure all Americans without requiring them to obtain coverage.
Senator Hillary Rodham Clinton of New York and John Edwards, the former North Carolina senator, support a mandate. It is, they say, the only way to guarantee that everyone is covered and to thereby bring down costs by spreading the country’s insurance risk as broadly as possible.
“The sad reality is that the uninsured don’t just struggle with costs themselves, they impose costs on the rest of us,” Mrs. Clinton said in September. “It’s a hidden tax: the high cost of emergency room visits that could have been prevented by a much less expensive doctor’s appointment, the cost of unpaid medical bills that lead insurance companies to raise rates on the rest of us.”
Mr. Edwards echoed those remarks a week later. “The reason the mandate is necessary is because you cannot have universal health care without it,” he said. “Does not exist, and anyone who pretends it is, is not being straight.”
Senator Barack Obama of Illinois sees it a different way. He argues there is danger in mandating coverage before it is clear it can be affordable for those at the margins. While Mr. Obama does not rule out a mandate down the road, his emphasis is on reducing costs and providing generous government subsidies to those who need them. He would mandate coverage for children.
That distinction set off a pointed exchange in the Democratic debate in Las Vegas on Nov. 15. “I don’t think that the problem with the American people is that they are not being forced to get health care,” Mr. Obama said. “The problem is they can’t afford it.”
Mrs. Clinton jabbed back, saying Mr. Obama’s plan “starts from the premise of not reaching universal health care,” a virtual slur in the Democratic campaign. Mr. Obama responded that Mrs. Clinton had yet to explain how she would enforce a mandate. “She is not garnishing people’s wages to make sure that they have it,” he pointed out.
Obama strategists had been considering that point of attack for several weeks. It served the purpose, they said, not only of separating the candidates on a crucial domestic issue, but also of reinforcing their message that Mrs. Clinton does not, in Mr. Obama’s words, provide “straight answers to tough questions.”
Mrs. Clinton discovered the peril of revealing too many policy details in 1993, when the 1,342-page health plan she developed for her husband attracted a legion of opponents. This year, she has said she would leave the particulars of enforcement to her negotiations with Congress.
The Massachusetts plan was signed into law by former Gov. Mitt Romney, who, like each of his rivals for the Republican presidential nomination, does not now support a national insurance mandate. The law, which requires adults to be covered by Dec. 31, grants exemptions from the penalty if an income-based formula determines that coverage would not be affordable.
State officials warned that if policies were not bought this month they were not likely to be in effect by the deadline. But some insurers said they would sell last-minute policies.
The state established a mild penalty for the first year: the loss of the $219 tax exemption. But in the second year, the fine can amount to half the cost of the least expensive policy available, probably at least $1,000.
Ann F. McEachern, 33, a waitress and student who lives in Cambridge, said she did not buy insurance this year but probably would in 2008. “The penalty in 2007 wasn’t enough to kick it up to the top of my priority list,” Ms. McEachern said. “It’s always nice to be insured, but I think I’m at pretty low risk for anything happening to me that would be financially devastating.”
Though officials do not yet have data to determine who the remaining uninsured are, they assume many are in the group they call “the young invincibles.”
“At 27, it’s not like I’m thinking, ‘Oh, man, what if I need an operation down the line?’ ” said Samuel B. Hagan of Lenox, a courier who remains uninsured. “Furthest thing from my head.”
John E. McDonough, executive director of Health Care for All, an advocacy group based here, said he found it breathtaking that political leaders were calling for an individual mandate well before there was any way to measure the success of the Massachusetts experiment.
But Diane Rowland, executive vice president of the Henry J. Kaiser Family Foundation, which studies health policy, said it had become broadly accepted “that an individual mandate is the only alternative to government provision of coverage if you hope to achieve universal coverage.”
That said, even Massachusetts officials acknowledge that their universal coverage plan is not likely to be universal anytime soon.
“There’s good evidence,” Mr. Kingsdale said, “whether it’s buying auto insurance or wearing seat belts or motorcycle helmets, that mandates don’t work 100 percent.” He added, “We’re talking about how close you can get to 100 percent, and to me it’s pretty evident you can’t get as close without the mandate as you can with it.”