Nothing.

Let me be more specific.  For years the GOP has made plenty of hay by pushing back against mis-characterized versions of the Democrats' party positions.  To take any kind of unified position on anything, especially Iraq is a serious tactical error. 

It is similar to assymetric warfare.  The Republicans' media machine is a finely tuned meatgrinder.  It whirrs into action when it detects anything it can push against.  The machine's existence is the sole reason a minority party whose positions differ widely from the majority of the American public remains in power. 

However, the GOP media machine can only push back.  Its inability to govern is now evident for all to see.  The Republican Party cannot run from its singularly atrocious record of governance.  The GOP can only hope that somehow they can change the subject. 

The worst thing the Democratic party can do now is to try and propose a major program on things which it did not create and cannot possibly hope to create solutions for.  Like Nixon's "Secret Plan" to end the war, this strategy relies on the fact that the election must be about the Republican's record in office, not the Democrats' own plans to fix the many broken windows around the house. 

This seems counterintuitive to many of those inside the Beltway, where I live.  But the simple fact is that the American public is fed up with grand plans and promises of glory.  They want a promise to govern well and that is all.