Factbox: Control of US Senate at Play in 10 Key Competitive Races
This year’s election year battle for control of the U.S. Senate is intensifying, as Republicans prepare to push through President Donald Trump’s Supreme Court nominee in the closing weeks of a campaign dominated by the…

This year’s election year battle for control of the U.S. Senate is intensifying, as Republicans prepare to push through President Donald Trump’s Supreme Court nominee in the closing weeks of a campaign dominated by the coronavirus pandemic.
Republicans hold a majority of 53 seats in the 100-seat Senate. But the number of competitive Republican seats has grown to include the one held by Senate Judiciary Committee Chairman Lindsey Graham, who is running neck and neck with Democrat Jaime Harrison in the traditionally Republican state.
Democrats would need to net at least three Republican-held seats for a majority, if Democrat Joe Biden wins the White House, giving his running mate Kamala Harris a tie-breaking Senate vote, or four seats if Biden loses.
Here is a look at eight races where Senate Republican incumbents are locked in highly competitive contests against Democratic challengers, and two where Democrats are on the ropes:
Vulnerable Republicans:
ARIZONA
Republican Senator Martha McSally lags Democratic challenger Mark Kelly in fundraising and trails him by an average of nearly 7 percentage points in opinion polls, according to the campaign tracking website RealClearPolitics.com.
McSally, a former U.S. representative and U.S. Air Force combat pilot, was appointed to the seat once held by the late Republican Senator John McCain after losing her 2018 Senate bid to Democrat Kyrsten Sinema. Kelly, a former astronaut and U.S. Navy combat pilot, has been leading McSally in opinion polls for more than a year.
COLORADO
Republican Senator Cory Gardner, a former U.S. representative who entered the Senate in 2015, is among the most vulnerable Senate Republicans partly because of his allegiance to Trump, in a state that has gone Democratic in the last three presidential elections.
Democrat John Hickenlooper, a former two-term governor and 2020 presidential hopeful, is leading Gardner in opinion polls. But Gardner holds a sizeable cash advantage and the Democrat’s polling lead has largely kept below the double-digit advantage he held in July, according to FiveThirtyEight.com.



