Mr. Cuccinelli and the plaintiffs in the Florida case, who include attorneys general or governors from 20 states, have emphasized that Congressional bill writers did not include a “severability clause” that would explicitly protect other parts of the sprawling law if certain provisions were struck down…

Without such language, the Supreme Court, through its prior rulings, essentially requires judges to try to determine whether Congress would have enacted the rest of a law without the unconstitutional provisions.

The Justice Department, which represents the Obama administration, acknowledges that several of the law’s central provisions, like the requirement that insurers cover those with pre-existing conditions, cannot work unless both the healthy and the unhealthy are mandated to have insurance. Otherwise, consumers could simply buy coverage when they needed treatment, causing the insurance market to “implode,” the federal government asserts.