The U.S. Supreme Court this week hears a challenge to President Barack Obama's health care overhaul. If successful, the lawsuit would cripple Obama's prized domestic achievement, a program that has brought the U.S. as close as it has ever come to universal health care.
The Affordable Care Act passed Congress in 2010 without a single Republican vote in favor.
An explanation of the legal case:
Four Words Determine the Law's Future