But polls show a slim majority of Americans are still opposed to Obama's plan. A Gallup survey taken earlier this month found that 45 percent favor and 48 oppose Obama's healthcare plan and that more Americans believe new legislation will make things worse for the United States as a whole.

And the latest Rasmussen Reports national telephone poll, taken on Friday and Saturday nights, shows that 41 percent of likely voters favor the health care plan and 54 percent oppose it, figures that are consistent with previous findings, the company said.

Stephen Weber, chief operating officer at the Program on International Policy Attitudes, said younger Americans stand among the plan's chief supporters, as many seniors already carry government health insurance.

And while some argue that young people's tax dollars will subsidize insurance for those in their 50s and early 60s, youth have expressed little concern.

"The evidence doesn't seem to be that people are voting simply in their economic interests," Weber said.

"There's a bit of a generational issue here," he said, adding that the young tend to be more open to change and that older people are more risk averse.

For African Americans and Latinos, Weber suspects they are aligning themselves with Obama on health care. "The issue tends to break around people's identification with Obama," he said, adding that Democratic voters usually support Obama's health care plan, whereas Republicans and independents tend to oppose it.

While there are millions of uninsured Americans, not all are poor. Some studies show that some Americans who can afford coverage opt not to purchase it, although there remain many cases of uninsured people who want coverage but can not afford it.

"Don," a mid-level employee at a major insurance company, who declined to be identified as he is not authorized to speak, said the bill does little to address the multiple factors responsible for what he billed as "out-of-control health care costs."

Those include sharply rising hospital inpatient and outpatient costs, which he said contribute a large chunk to rising medical costs. Recent reports have also shown that higher prices are the result of hospital and physician groups' growing power to negotiate higher rates, he said.

Brand-name drug prices increased significantly, and rising treatment volumes and a higher incidence of chronic disease, such as diabetes and high blood pressure, are also making health care more expensive, he said.

"The bill missed the point," he said, but added that one of the legislation's benefits is that it forbids companies from dropping people when they become ill. "If you drop people when they get sick, what's the point of getting insurance?" he asked.

Some have labeled the new law a boon for Americans.

"For the first time in our country's history, health care will deliver stability and security to the middle class by improving the quality of health care coverage, ensuring better access for those who lack coverage, and laying the foundation for controlling health care costs," said Jonathan Cowan, president of Third Way, in a statement.

But Edwin J. Feulner, president of the Heritage Foundation, a think tank, said in a statement that the bill passed in the face of overwhelming opposition from those who believe it will accelerate Washington's intrusion into people's lives.