Independent Joe Lieberman is driving Gail Collins and the progressive left crazy.  He caucuses with the Democrats and holds a plum committee chairmanship on the strength of largely voting with the Democrats.  But he is threatening to filibuster the healthcare reform vote in the Senate.  The only way to give him the incentive to drop this threat is to threaten him in turn – strip him of his chairmanship if he filibusters the vote.

The problem is that Lieberman knows that if he filibusters, the Democrats do not have the incentive to carry out their threat because they need his vote in the future.  Their threat to strip him of his chairmanship is not credible. This is a classic issue in deterrence theory: how can we make our threat to bomb the Soviets if they bomb us credible?  Many of the strategies do not transfer (e.g. the automated response à la Doomsday machine in Dr. Strangelove), but one does: the Democratic leadership has to rely on reputational devices to incentivize Lieberman.

Forgiving Lieberman may create future defections as the Democratic leadership shows they are wimps.  Carrying out the threat shows that Reid and Obama are tough and signals they will be tough in the future.   This is the slippery slope argument and the classic “act crazy to get a reputation for toughness” strategy.  Dick Cheney gets this strategy (though it seems to be the only strategy in his arsenal).

If Lieberman finds the threat credible,  the Democrats do not even have to carry it out because he will not filibuster.  But if he does not find it credible, he will filibuster.  Then you face the problem of losing his vote in the future if you accept the slippery slope argument and feel you must punish Lieberman for his treachery.

To evaluate this possibility, we have to consider the credibility of Lieberman’s threat to vote Republican in the future if he stripped of his chairmanship.  The Republicans are too extreme for the Connecticut voter.  If Lieberman votes with them or switches parties, he is in trouble at home.  So you can rely on his reelection motive to discipline him and get his vote on some mainstream Democratic issues.

There is also a subtle way to give Lieberman the incentive to go along with his punishment without ganging up with the Republicans.  It is a “penal code” to design dynamic incentives and it was discovered by Dilip Abreu.  The penal code boils down to forgiving Lieberman gradually over time to get his cooperation in the future.  In this scenario, this requires some deviation from standard seniority principles for allocation of committee chairs.  Put a stopgap person, Al Franken, in charge of Lieberman’s committee. Tell Lieberman that Franken will step down if Lieberman is on board in future.  Otherwise, goodbye chairmanship forever.  If this subgame is triggered as Lieberman is bloody minded, Franken should step down in favor of whoever is in line for the chairmanship now if  Lieberman is ejected.  This might be necessary to get this person on board with the plan to deviate from the status quo procedure for allocation of committee chairs.

And if all this Machiavellian structure falls apart, Al Franken is Chair of an important committee.  He is a professional comedian while the rest of the Senate are amateurs.  That seems like an improvement to me.