Under the law, Watson and nearly 62,000 other “uninsurable” patients are getting coverage through a little-known program for people who have been turned away by insurance companies because of pre-existing medical conditions.

“Without it, I would have been dead on March 2,” Watson said of the Pre-Existing Condition Insurance Plan, known as PCIP. That’s when she was hospitalized for a life-threatening respiratory infection.

It’s not clear how the Supreme Court will rule on Obama’s law, but Watson’s case illustrates the potential impact of tying everything in the far-reaching legislation to the fate of one provision, the unprecedented requirement that most Americans carry health insurance.

Weighty matters.