Stop Me Before I Vote Again

After their stunning loss of both houses of Congress in 1994, the Democrats have averaged over 50% of the vote in Congressional races in every year except 2002, yet they have not regained control of the House. The same is true with the Senate: in the last three elections (in which 100 senators were elected), Democratic candidates earned three million more votes than Republican candidates, yet they are outnumbered by Republicans in the Senate as well. 2006 is looking better for the Democrats, but our calculations show that they need to average at least 52% of the vote (which is more than either party has received since 1992) to have an even chance of taking control of the House of Representatives.

Why are things so tough? Looking at the 2004 election, the Democrats won their victories with an average of 69% of the vote, while the Republicans averaged 65% in their contests, thus "wasting" fewer votes. More formally, we estimated the seats-votes curve for 2006 by constructing a model to predict the 2006 election from 2004, and then validating the method by applying it to previous elections (predicting 2004 from 2002, and so forth). We predict that the Democrats will need 49% of the average vote to have a 10% chance, 52% of the vote to have an even chance, and 55% of the vote to have a 90% chance of winning the House.