MONDAY, Nov. 14 (HealthDay News) -- The U.S. Supreme Court agreed on Monday to hear challenges to President Barack Obama's health reform legislation, with a decision expected in June on whether some parts of the controversial initiative are constitutional.

The decision could possibly turn the 2012 presidential election into a referendum on Obama's ambitious plan to provide health care to all Americans.

Obama signed the Patient Protection and Affordable Care Act into law in March 2010 and, since then, certain provisions have been enacted, such as prohibiting insurers from denying coverage to people with pre-existing conditions and requiring insurers to allow children to stay on their parents' coverage plans until they are 26.

The law aims to extend insurance coverage to more than 30 million Americans, through an expansion of Medicaid and the provision that people buy health insurance starting in 2014 or face a penalty.

Challenges to the law have been heard by four lower courts, only one of which struck down the law's central provision, the so-called "individual mandate," which requires all Americans to purchase health insurance or be fined. The mandate is integral to the reform plan because, in theory, it brings premium rates down as part of state-managed insurance "pools."

Republicans and free-market advocates have charged that the mandate is unconstitutional, giving Congress too much authority to tell Americans what to do.

"The administration is vulnerable because they've never been able to draw a line on what Congress can require people to do and some of the things they can't," said John Goodman, president of the National Center for Policy Analysis, a nonpartisan, nonprofit think tank focused on free-market approaches to public policy.

"At hearings and court arguments we've heard the question over and over asked, 'Can the federal government require us to drink orange juice every day? Can it require us to eat broccoli?' " added Goodman, who believes the mandate will be struck down. "People come up with ridiculous scenarios, and the administration has never had a decent answer to that."

Michael Russo, a health care policy analyst with U.S. Public Interest Research Group, disagreed, saying he felt the individual mandate will be upheld by the Supreme Court.

If the law were struck down, he said, it would be "chaos."

"A lot has already been done to implement the law and to build new reforms on top of it," Russo said. "If the law got struck down, everything done on health care in the last year-and-a-half would be in jeopardy. It's unclear which of the reforms could move ahead."

Reacting to Monday's announcement by the Supreme Court, White House spokesman Dan Pfeiffer said in a statement: "We are pleased that the court has agreed to hear this case. We know the Affordable Care Act is constitutional and are confident the Supreme Court will agree."

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," the Associated Press reported.

"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," he said.

In March, a Harris Interactive/HealthDay poll found that only 22 percent of Americans support this provision although they did favor other elements of the plan, such as health insurance exchanges that will allow consumers to shop for coverage and tax credits so small businesses can afford coverage for employees.

Prior Harris Interactive/HealthDay polls consistently found that the individual mandate is the only part of the Affordable Care Act that is unpopular with a majority of Americans.

In line with public thinking, Goodman feels that many of the law's provision will be left in place.

Of course, it will be impossible to know what the future of American health care coverage will look like until the Supreme Court does hand down its much-anticipated ruling.

"If the mandate goes away, that's one thing. If the mandate doesn't go away, that's another thing," said Russo.

Ron Pollack is executive director of Families USA and a lawyer who has argued cases before the Supreme Court. He said: "If the Supreme Court decides that the individual responsibility provision is not constitutional then they have to decide should this have any effect on any other part of the statute. Of the four courts that have issued rulings, three of them did not in any way invalidate the individual responsibility provision, and the one court that [did] also upheld that other provisions of the statute should not be affected by the ruling.

"While my own presumption is that the Affordable Care Act will be upheld in its entirety to be constitutional, one of the things I've learned is that you never hazard a guess," he added.

More information

For more on the Affordable Care Act, visit HealthCare.gov.