In the end, most of the arguments about President Barack Obama’s health care overhaul turned out to be beside the point.

The law’s defenders for the most part argued that Congress can require people to buy health insurance because the Constitution lets it regulate commerce “among the several states.” Their fallback argument was that Congress can impose the requirement because the Constitution gives it the power to make “all laws which shall be necessary and proper for carrying into execution” its regulations.

Opponents concentrated on knocking those arguments down. Most people on both sides assumed that the individual mandate would stand or fall on those grounds. So the conventional wisdom wasn’t just wrong about the outcome of the case – a much more severe blow to the law was expected – it was wrong about what the case would, in the minds of the justices, be about.