The Wisconsin Democrats got some good news in yesterday's special election, as they captured a long-held Republican assembly seat (the other two seats up for election were strongly Republican). Democrats see this as a very good sign for their recall campaigns. Unquestionably, it is a positive, but how much of a good sign?
As I've mentioned before, one of the advantages of the recall is that it is a special election, which historically have much lower voter turnout. The result is that the angry party (the recall proponents) have an easier time motivating their base and getting people to go out to the ballot box for one race. For a particularly Wisconsin-focused example, in the last Senate recall, Gary George in 2003, turnout was very low (can't find a link, but I have a contemporary AP story that cites 8%).
However, there are exceptions to the lower vote turnout rule. Gray Davis was one (voter turnout much higher in the recall than in 2002 general election), Scott Brown arguably another. No guarantees, but there is a good chance that due to the atmosphere surrounding the Wisconsin recalls, we will see a higher voter turnout than in the 2010 general elections.
Let's look at the turnout results from the special election. Turnout was much lower for the special than in general election in November 2010 (23,747 people voted for the seat in November versus 15,588 in the special). However, equally unsurprisingly, the one contested seat saw much higher turnout than the two safe Republican seats (11,208 and 9,688). So, people are motivated, but the assembly seat (which also mattered a great deal less, as the Republicans still maintain a formidable majority in the Assembly), didn't see a massive vote. So, a good sign for the Democrats, but I wouldn't read too much either way.