Get the best odds on which party will win the 2020 US Senate election. Know the chances that Republicans and Democrats have to control the Senate after 2020 according to the latest data provided by the biggest political betting markets. The current Senate is controlled by the Republican Party, who has 53 seats against 47 for the Democratic Party. There are 12 Democratic seats and 23 Republican up for election in 2020. Democrats will need to gain 3 or 4 seats to take control.