Monday: Arguments centered on whether the justices -- under the 1867 Anti-Injunction Act -- cannot rule on challenges to federal taxes until the levies are assessed. If it finds that the act applies, the clash would be delayed until after 2015.
Tuesday: The justices heard the main issue: the insurance requirement. The Obama administration said Congress could enact that provision under either its constitutional power to regulate interstate commerce or its authority to impose taxes. The court's more conservative justices suggested that a 5-4 decision to strike down the law was a real possibility.
Wednesday: The court heard arguments on what happens to the rest of the law if the insurance requirement is found unconstitutional. It also heard arguments about whether the law, by expanding the Medicaid program, unconstitutionally coerces the states into spending more on health care for the poor.