The U.S. Supreme Court heard oral arguments Tuesday on the heart of the case against the Affordable Care Act, known by detractors as "Obamacare".
Several states say the new health care law should be declared unconstitutional because it mandates that all Americans buy coverage.
Obama administration lawyer Donald Verrilli argued a mandate is allowed because health care is in crisis.
"For more than 40 million Americans, the system does not work," Verrilli told the court.
Conservative justices didn't seem to agree.

"So can the government require you to buy a cell phone because that would facilitate responding when you need emergency services?" asked Chief Justice John Roberts.
Liberals countered that everyone gets health care, even those who have no insurance.
That's simply not fair, said Justice Ruth Bader Ginsburg.

"The people who don't participate in this market are making it much more expensive for the people who do," she countered.
The swing vote could be Justice Anthony Kennedy.

He wrestled with the claim that a health insurance requirement might be constitutional.
"The young person who is uninsured is uniquely proximately very close to affecting the rates of insurance and the costs of providing medical care in a way that is not true in other industries," Kennedy noted.
Outside, both sides rallied, but the decisive battle, will be among the nine justices.
With Justice Kennedy not signaling support for the individual mandate, court watchers are guessing that the Affordable Care Act now looks more likely to be declared unconstitutional.
The decision comes in a few months.