The supercommittee seems likely to deadlock, which means reductions in projected defense and domestic discretionary spending will automatically become law. If that happens, I assume that Republicans will try to increase defense and Democrats domestic spending — but in each case they will face the burden of getting both chambers of Congress and the president to go along with the change.
In the interim the obvious liberal strategy will be to set pro-defense and anti-tax activists against each other. The price of staving off cuts to defense, they will say to defense hawks, is a balanced deal from the supercommittee that includes net tax increases. The price of keeping taxes low, they will say to anti-taxers, is to accept cuts in defense. (Some of the anti-taxers will see this as a side-benefit rather than a price.) Either way conservatives, most of whom want to keep taxes down and defense spending up, lose something.
But it seems as though there is an obvious counter-strategy: Pit domestic discretionary spending against middle-class entitlement spending. Liberals know that middle-class entitlement spending is more valuable to them politically, but they care more about discretionary spending. So the Republicans could hold the line on taxes while also advancing entitlement reforms that (1) spare the poor as much as possible, (2) yield savings within the budget window, and (3) don’t cross any ideological red lines for the Democrats. I think the Coburn-Lieberman Medicare reforms, though not perfect, would be a good template for Republicans on the commission to work with.
In effect the Republicans would be saying: Accept these entitlement reforms, or we’ll let the automatic cuts to both defense and domestic discretionary spending become law and see which side is more likely to get those cuts reversed in the political process. Would it work? Probably not. But it could work, it seems like the best available strategy, and it would keep the focus of the debate off intra-Republican strife.