No matter the outcome, the Supreme Court's ruling on the health care law's individual mandate will be seismic.
To strike the entire law would badly wound a sitting president and the century-long campaign for universal coverage. To uphold its intensely unpopular individual mandate would turn the U.S. Constitution on its head, and spark a backlash by independents and Republicans that could replace this president with one who has vowed to repeal the law.
What if the court only strikes the mandate? In 2009, Obama himself told Congressthat "requiring insurance companies to cover pre-existing conditions just can't be achieved" unless individuals are "required to carry basic health insurance." As proof, the law's rules governing pre-existing conditions caused the markets for child-only health insurance to collapse in 17 states before they even took effect.
The health insurance lobby, which spent $100 million to stop the bill from passing, is already sounding the alarm. If only the mandate falls, expect insurers to come out with both guns blazing against those supposedly popular rules.
Another mortal blow would come when state officials realize they can prevent the law from taxing employers in their state simply by refusing to implement the law's health insurance "exchanges." Without exchanges and the employer mandate, the health care law collapses. (And when those states learn the I.R.S. is trying to tax their employers anyway, without statutory authority, expect yet another round of lawsuits.)
The court could easily hand the law's opponents a loss. It's harder to imagine how the few people who actually support this law can win.