It is not clear how fully the public understands the complexities of the government plan proposal, and the poll results indicate that those who said they were following the debate were somewhat less supportive.

But they clearly indicate growing confidence in the government’s ability to manage health care. Half of those questioned said they thought government would be better at providing medical coverage than private insurers, up from 30 percent in polls conducted in 2007. Nearly 60 percent said Washington would have more success in holding down costs, up from 47 percent.

Sixty-four percent said they thought the federal government should guarantee coverage, a figure that has stayed steady all decade. Nearly 6 in 10 said they would be willing to pay higher taxes to make sure that all were insured, with 4 in 10 willing to pay as much as $500 more a year.

And a plurality, 48 percent, said they supported a requirement that all Americans have health insurance so long as public subsidies were offered to those who could not afford it. Thirty-eight percent said they were opposed.

In a follow-up interview, Matt Flurkey, 56, a public plan supporter from Plymouth, Minn., said he could accept that the quality of his care might diminish if coverage was universal. “Even though it might not be quite as good as what we get now,” he said, “I think the government should run health care. Far too many people are being denied now, and costs would be lower.”

While the survey results depict a nation desperate for change, it also reveals a deep wariness of the possible consequences. Half to two-thirds of respondents said they worried that if the government guaranteed health coverage, they would see declines in the quality of their own care and in their ability to choose doctors and get needed treatment.

“It is the responsibility of the government to guarantee insurance for all,” said Juanita Lomaz, a 65-year-old office worker from Bakersfield, Calif. “But my care will get worse because they’ll have to limit care in order to cover everyone.”