Provisionally, it looks like the following: In a little over a week, the shutdown has increased the probability of a Democratic House takeover in 2014 from 13% to as high as 50%.
Nate Silver: Nate Silver on the U.S. government shutdown:
For the most part, the experts you see on television are much too sure of themselves. That's been my impression of the coverage of the shutdown… folks… making too much of thin slices of polling and thinner historical precedents that might not apply this time around…. So what can we say?…. 1. The media is probably overstating the magnitude of the shutdown's political impact…. 2. The impact of the 1995-96 shutdowns is overrated in Washington's mythology…. 3. Democrats face extremely unfavorable conditions in trying to regain the House…. 4. The polling data on the shutdown is not yet all that useful….
The increasing extent of GOP partisanship is without strong recent precedent, and contributes to the systemic uncertainty about political outcomes…. The degree of polarization in the Congress is higher than at any point since the Great Depression by a variety of measures, and is possibly at its highest point ever. (Most of the evidence suggests the trend is asymmetric: Republicans in Congress have become much more conservative, while Democrats have become only somewhat more liberal.) What this means is that… conceptions based on recent history… may not be all that reliable…. There's a lot we don't know.