Congress is debating a new “mental health parity” law, which would require those who purchase mental health care coverage to buy the same amount of mental health care coverage as medical and surgical coverage.

The Congressional Budget Office (CBO) just released this not-too-technical summary. The CBO projects that the law would increase the cost of employer-sponsored health insurance by 0.4 percent. That means it could add another $46 to the (already rising) cost of a job-based family plan. Not a huge amount. But every little bit hurts. And Congress wonders why the number of Americans without health insurance keeps rising.

Of all the purposes government might serve, there can be none higher than telling people how much insurance they should purchase for mental health care, if they purchase insurance for mental health care.