(CBS News) Washington - The Supreme Court was to hear arguments Tuesday on the most significant part of President Obama's health care law: the requirement that everyone have health insurance.
Demonstrators were already showing up in the early morning.
The justices began considering the controversial law Monday.
Outside the building, people for and against the law made their voices heard.
Inside, the debate was technical and cerebral, as the justices delved into challenges over the 2,700-page measure.
Critics contend he case raises fundamental questions of federal power over American lives.
But on day one, they dealt with a basic legal question: Is it too soon for the court to hear the case?
At issue is whether the "penalty" people will pay for refusing to buy insurance amounts to a tax. If it does, the argument goes, the court can't hear the case until someone actually pays the tax -- which won't happen until 2015, when that part of the law is slated to go into effect.
Some of the justices were skeptical, such as Stephen Breyer, who said, "They called it a penalty and not a tax for a reason. They wanted it to fall outside that. It's in another chapter, etc."
But the arguments Tuesday were to center on the most controversial part of the law -- the individual mandate.
The court was to hear from opponents, including 26 states that say Congress has no power under the Constitution to tell anyone to buy anything. Under the Constitution's Commerce Clause, Congress has power to "regulate commerce." Opponents say, yes, that's true, but they can't create it.
The Obama administration is countering, saying health insurance is unique because, unlike all other products -- everyone needs health care.
The justice's questions during Tuesdays historic arguments were expected to yield hints about how they were leaning.
Overall arguments were scheduled to wrap up Wednesday.
To see Jan Crawford's report, click on the video in the player above.