Today's arguments hit the core of the Affordable Care Act: the mandate that requires just about everyone to have health insurance starting in 2014.
And the U.S. Supreme Court's justices appeared split on whether the federal government can force people to buy health insurance. The court's conservatives appeared skeptical and unmoved by the government's arguments in favor of the mandate.
"The government had a hard time, and if they win, they win narrowly," NPR's Nina Totenberg reported from outside the court. "I don't think you can call this."