In this classic game-theory case, you and a professional associate are both arrested for theft. If neither of you talks, then you’ll probably get off. But if just one of you talks, then the person who talks will get a reduced sentence, while the other person has the book thrown at them. If you both talk, then both of you go to jail for a long time. The equilibrium is for both of you to talk, just in case the other guy does . . . which is why criminal gangs go to such elaborate lengths to build up trust and dispense punishment for snitches.

Insurers and Democrats are now in a similar situation. Legislators need insurers to help them make this law work by staying in the market and selling policies for affordable premiums. Insurers need legislators to hold this law together, particularly the individual mandate. If both of them hold strong, then Democrats have their best chance to get Obamacare working, and they can hope that voters like it so they can win re-election. Insurers, meanwhile, get a system in which the public is legally required to buy their product.

But if you think the other side might waver, then your best move is to defect immediately. If insurers stand strong but politicians end up repealing the mandate, then they will have lost a bunch of money for nothing. If politicians stand strong but insurers raise prices and/or exit the market, they’ll get slaughtered at the polls.

The moment that it looks like there’s a big risk that Obamacare won’t work, both Democrats and insurers are going to stampede for the exit.