It's well known that Republicans have a big advantage in the Electoral College, which caused Trump to win the 2016 election despite losing the popular vote by about 2% and made the 2020 election a lot closer than it otherwise would have been. The purpose of this market is to determine just how big that advantage will be this cycle by estimating how much the Democratic nominee needs to win the popular vote by in order to actually win the election. 

This market will resolve to the option that correctly states the Democratic margin of victory in the popular vote, followed by whether Democrats win or lose the Electoral College. In the event of an Electoral College tie, the Electoral College winner is whatever person is selected by the House of Representatives.