Updated at 4:13 p.m. ET
WASHINGTON - The Supreme Court said Monday it will hear arguments next March over President Obama's health care overhaul a case that could shake the political landscape as voters are deciding if Mr. Obama deserves another term.
This decision to hear arguments in the spring sets up an election-year showdown over the White House's main domestic policy achievement. And it allows plenty of time for a decision in late June, just over four months before Election Day.
"The court could endorse the measure, it could say the law is constitutional; it could strike it down and say it's not," said CBS News senior legal analyst Andrew Cohen. "Or the justices could not agree, and they could decide to delay it for a while. That's happened before in certain high-profile cases. I can't imagine it would happen again, but, look, anything's possible."
The justices announced they will hear an extraordinary five-and-a-half hours of arguments from lawyers on the constitutionality of a provision at the heart of the law and three other related questions about the act. The central provision in question is the requirement that individuals buy health insurance starting in 2014 or pay a penalty.
In the modern era, the last time the court allotted anywhere near this much time for arguments was in 2003 for consideration of the McCain-Feingold campaign finance reform. That case consumed four hours of argument. This argument may spread over two days, as the justices rarely hear more than two or three hours a day.
The 2010 health care overhaul law aims to extend insurance coverage to more than 30 million Americans, through an expansion of Medicaid, the requirement that individuals buy health insurance starting in 2014 or pay a penalty and other measures. The court's ruling could decide the law's fate, but the justices left themselves an opening to defer a decision if they choose, by requesting arguments on one lower court's ruling that a decision must wait until 2015, when one of the law's many deferred provisions takes effect.
"We know the Affordable Care Act is constitutional and are confident the Supreme Court will agree," communications direct Dan Pfeiffer said in a statement.
The Justice Department said it was confident that the law is constitutional.
"Throughout history, there have been similar challenges to other landmark legislation such as the Social Security Act, the Civil Rights Act, and the Voting Rights Act, and all of those challenges failed," a department spokesperson said in a statement. "We believe the challenges to the Affordable Care Act will also ultimately fail and that the Supreme Court will uphold the law."
House Minority Leader Nancy Pelosi said Monday she was also confident that the Supreme Court would uphold the law.
"Millions of our nation's families, seniors, young adults, and workers are already benefiting from the law," she said.
House Speaker John Boehner called the law a "government takeover of health care" that's "threatening jobs, increasing costs and jeopardizing coverage for millions of Americans."
"The American people did not support this law when it was rushed through Congress, and they do not support it now that they've seen what's in it," Boehner said.
Senate Republican Leader Mitch McConnell of Kentucky called the law an "unprecedented and unconstitutional expansion of the federal government into the daily lives of every American."
"In both public surveys and at the ballot box, Americans have rejected the law's mandate that they must buy government-approved health insurance, and I hope the Supreme Court will do the same," McConnell said.
Republicans have called the Patient Protection and Affordable Care Act unconstitutional since before Mr. Obama signed it into law in March 2010. But only one of the four federal appeals courts that have considered the health care overhaul has struck down even a part of the law.
The federal appeals court in Atlanta said Congress exceeded its power under the Constitution when it adopted the mandate. The federal appeals court in Cincinnati upheld the entire law, as , in recent days.
The case could become the high court's most significant and political ruling since its 5-4 decision in the Bush v. Gore case nearly 11 years ago effectively sealed George W. Bush's 2000 presidential election victory.
In addition to deciding whether the law's central mandate is constitutional, the justices will also determine whether the rest of the law can take effect even if that central mandate is held unconstitutional. The law's opponents say the whole thing should fall if the individual mandate falls.
The administration counters that most of the law still could function, but says that requirements that insurers cover anyone and not set higher rates for people with pre-existing conditions are inextricably linked with the mandate and shouldn't remain in place without it.
The court also will look at the expansion of the joint federal-state Medicaid program that provides health care to poorer Americans, even though no lower court called that provision into question. Florida and the 25 other states say the law goes too far in coercing them into participating by threatening a cutoff of federal money. The states contend that the vast expansion of the joint federal-state Medicaid program and the requirement that employers offer health insurance violate the Constitution. No appeals court has agreed.
"The court recognized the seriousness of these vitally important constitutional challenges by allocating an extraordinary amount of time for oral argument," Florida Attorney General Pam Bondi said.