Here's how this works:

This market closes the day before Election Day.

Once the final margins are known for every state in the U.S. - likely at some point in early December - this market will resolve as follows:

Most Democratic state, by margin: YES
Second-most Democratic state: PROB 98%

Third-most Democratic state: PROB 96%

. . . (etc.) . . .

Third-least Democratic state: PROB 6%

Second-least Democratic state: PROB 4%

Least Democratic state: PROB 2%

D.C. is not included, and neither are the individual congressional districts of Nebraska and Maine.

This creates an incentive structure for Manifold to correctly order the states of the U.S. from most Democratic to least - a very difficult task, and one I'm curious to see how well this site can pull off!