Here’s another way to think about it. Some people choose not to get insurance, even when it is available to them, primarily because they think they’ll never get sick or injured and are willing to risk the consequences. Without a mandate, they’re more likely to remain uninsured.

But some people choose not to get insurance because it seems (and frequently is) too expensive, at least relative to the benefits they’d get. If your household income is $40,000 a year and the annual premiums for family coverage add up to $12,000, with huge out-of-pocket costs and gaps in coverage, why would you bother? The law’s subsidies and, to a lesser extent, regulations on benefits should alter that calculus: Coverage will start to seem like a much better deal and many of these people will start buying. The net effect will be to bring many more people into the insurance pool, many of them relatively healthy, making it possible for insurers to spread the cost of high medical bills more broadly and keep costs down…

If five justices are determined to rule against the mandate, I still hope they adopt the approach that Joey Fishkin of the University of Texas has proposed: Striking down the insurance requirement but leaving in place the financial penalty that goes with it. That would establish a constitutional principle (one I wouldn’t like) while, most likely, allowing the Affordable Care Act to function more or less as its architects intended. But if five justices go farther and strike the entire mandate, including the fee, they still might not cripple the law. They might merely weaken it, if—and it’s a huge if—they leave in place everything else.