How big is the Senate’s pro-Republican bias? Consider the 2020 election. Drawing on the tipping state logic above, there is a five-point gap between the 2020 presidential election results in the median state—the one that yields a Senate majority—and the 2020 national presidential vote. This means that the Senate’s partisan bias was such that Democrats had to win the nationwide popular vote for Senate by about five points to gain control of the Senate.
