“This only works if young people show up,” said Bill Clinton the other day. He was explaining Obamacare.

In other insurance markets, a person newly entering an insurance pool will be charged a premium that reflects the expected cost and risk the individual brings to the pool. With respect to life insurance, disability insurance, homeowner’s insurance, and (for the most part) even auto casualty insurance, you pay for what you get.

Why are things so different in the market for health insurance? Because in this market, premiums are regulated, and that regulation is completely dominated by the idea that it’s unfair to charge real premiums.