Sen. Ben Sasse, R-Neb., has warned that President Donald Trump “will take the Senate down with him” if he loses to Democratic nominee Joe Biden. In a private call Wednesday with constituents, Sasse said he feared a “Republican bloodbath” for the Senate in the November election, saying “we are staring down the barrel of a blue tsunami.”

Sen. Ted Cruz, R-Texas, has also said November could be a "bloodbath of Watergate proportions." He said voters may take their anger out on Republicans due to the pandemic and state of the economy. 

Democrats will need three or four seats to take the Senate, depending on whether Biden wins the White House. The most promising Senate races for Democrats are in Arizona, Colorado, North Carolina, Maine and Iowa, but upset victories are also possible in Montana, South Carolina, Kansas, Alaska, Georgia and Texas. 

Trump’s influence over the party has hurt Republicans in down-ballot races. “The Senate map is looking exceedingly grim,” Dan Eberhart, a major GOP donor, told the Associated Press.

Some Republicans have sought to distance themselves from Trump. Vulnerable Sen. Martha McSally of Arizona refused to say she was proud of the president during a recent debate with Democratic challenger Mark Kelly.

Other Republicans have become out-fundraised by their Democratic opponents, making the path to reelection steeper. Republican Sen. Lindsey Graham of South Carolina has pleaded for donations on Fox News, in order to keep up with Democratic challenger Jaime Harrison.

The Democrats last controlled the Senate during the 113th Congress, from January 2013 to January 2015. Democrats took back the House of Representatives during the 2018 midterm elections.