Many, many years ago I lived in a graduate dorm with a fellow working on a PhD in government. He was employed at an institute in Southern California, charged with drawing alternative state and Congressional district boundaries; i.e., he was a gerrymanderer. And in drawing boundaries the goal is always to make sure the safe Democrat seats had as many Democrats as possible, and the safe Republican seats still had a significant fraction of Democrats, to negate their effects on the election. (My roommate worked for a institute that was hired by the California GOP.) Doing so would naturally create more "safe" Republican districts, but they would be by design less "safe" than Democratic districts, since you want 75-80% Democrat shares in the safe blue districts and 60-65% Republican shares in the safe red ones.

Obviously both sides play this game -- this isn't rocket science. But the ability to enforce this kind of gerrymandering depends on which party controls the various state legislatures right after the decennial Census. In the 2000 election, the number of state legislatures that were controlled by Democrats fell from 19 to 16; the share of Republican state legislatures held constant, so that the three that the Democrats lost were lost because only one house changed. And the governor's mansions have been increasingly red, with 31 Republican governors in 2001-02.

The impact of this is that Republicans can spread their votes out in enough districts to create majorities in Congress and state legislatures without actually receiving 50% of the votes.

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 (during which 100 senators were elected), Democratic candidates have 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. The Republicans won 47 races with less than 60% of the vote; the Democrats only 28. Many Democrats are in districts where they win overwhelmingly, while many Republicans are winning the close races--with the benefit of incumbency and, in some cases, favorable redistricting.

This explains why, in a generally down year for the party in power -- Year 6 of a two-term President -- and with this kind of districting, Republicans look so perilously close to electoral disaster, yet seem to be heartened. The map plays exactly as the optimists (like Hugh) say: If you can really turn out Republican voters, you can win your safe districts and the Congress, but you have a smaller margin for error than the Democrats do. Democrats, knowing this, are wisely engaged in the politics of voter suppression -- their best road to victory isn't to turnout their own voters as much as it is to keep Republicans discouraged and at home on November 7th. And it's why the polls' assumptions on voter turnout matter so much and give you such different conclusions.