Administration defends health-law changes

Florida and 25 other states, including Pennsylvania, as well as the National Federation of Independent Business, told the court in separate briefs that if the justices strike down the individual requirement, they should invalidate the rest of the law as well. Thirty-six Republican senators echoed the states' argument in their own filing.

The law is aimed at extending health insurance coverage to more than 30 million previously uninsured people and would, by 2019, leave just 5 percent of the population uninsured, compared with about 17 percent today, according to the Congressional Budget Office. About half of the increase would come from the individual requirement; the rest would come from an expansion of Medicaid and other provisions.

The health-care law has drawn intense opposition from Republicans; the party's presidential candidates have all vowed to repeal it if elected. The individual insurance requirement has been a lightning rod because it requires people to buy a product from a private insurer or pay a penalty.

But the administration said the requirement falls within Congress' power under the Constitution's Commerce Clause because health care is an issue of supreme national importance that consumes nearly 18 percent of the U.S. economy.

People may lack insurance, but they still get health care, and the costs get passed on the insured, the administration said.