The Supreme Court on Thursday upheld President Obama's health care law in a complex opinion that gives the president a major election-year victory.
The historic 5-4 decision will affect the way Americans receive and pay for their personal medical care.
Chief Justice John Roberts announced the decision that allows the law to go forward with its aim of covering more than 30 million uninsured Americans.
A majority of the justices said that the individual mandate — the requirement that most Americans buy health insurance or pay a fine — is constitutional as a tax.
"Because the Constitution permits such a tax, it is not our role to forbid it, or to pass upon its wisdom or fairness," wrote Roberts.
The court's four liberal justices, Stephen Breyer, Ruth Bader Ginsburg, Elena Kagan and Sonia Sotomayor, joined Roberts in the outcome.
Conservative Justices Samuel Alito, Anthony Kennedy, Antonin Scalia and Clarence Thomas dissented.
Roberts — a conservative appointed by President George W. Bush— provided a key vote to preserve the landmark health care law, which figures to be a major issue in Obama's re-election bid against Republican opponent Mitt Romney.
The government had argued that Congress had the authority to pass the individual mandate as part of its power to regulate interstate commerce; the court disagreed with that analysis, but preserved the mandate because the fine amounts to a tax that is within Congress' constitutional taxing powers.
As lawyers examined the details of the various opinions, political analysts quickly predicted at least a short-term political boost for Obama.
Peter A. Brown, assistant director of the Quinnipiac University Polling Institute, said "you can hear the sigh of relief at the White House" over a big plus for Obama.
"It allows the president's signature achievement to stand," Brown said. "Since politics is the ultimate zero-sum game, what's good for Obama is bad for Gov. Mitt Romney."
Brown also noted that the ruling allows the Republican "to continue campaigning against the law and promising to repeal it."
The Republican-controlled House will vote July 11 for a full repeal of the health care law. It is a symbolic move that stands no chance of passage in the Democratic controlled Senate. House Budget Chairman Paul Ryan, R-Wis., acknowledged that the election will be a determining factor for the law's fate and the GOP's ability to overturn it. "It's up to the American people in the next election and their representatives to determine the fate of this law."
Other congressional Republicans vowed to step up efforts to repeal what they call "Obamacare," should they win control of Congress in the November elections.
"The president's health care law is hurting our economy by driving up health costs and making it harder for small businesses to hire," said House Speaker John Boehner, R-Ohio. "Today's ruling underscores the urgency of repealing this harmful law in its entirety."
The law's individual mandate had been the key question for the court.
Critics called the requirement an unconstitutional overreach by Congress and the Obama administration; supporters say it is necessary to finance the health care plan.