Former Vice President Joe Biden enjoys a comfortable lead against President Donald Trump in the polls as Americans cast their votes. But even if he ousts Mr Trump from the White House, Mr Biden will not be able to advance much – or any – of his agenda if his party does not assume control of both branches of the US Congress.
Polling aggregator FiveThirtyEight gives Democrats a 95 per cent chance of retaining control of the House of Representatives. Democrats are also favoured to take away control of the Senate from Republicans.
FiveThirtyEight gives the party a 75 per cent chance of winning enough seats to control the Senate as Democratic candidates threaten vulnerable Republicans who have tied themselves closely to Mr Trump.
Republicans currently hold 53 Senate seats to the Democrats’ 47 seats. As such, Democrats must win three additional seats to assume Senate control if Mr Biden wins, or four if Mr Trump wins since the vice president presides over tie votes.
Of the 35 Senate seats up for grabs this year, Republicans are defending 23 while Democrats are only defending 12. FiveThirtyEight’s analysis ranks the most competitive states as Iowa, Georgia, North Carolina, Montana and Maine.
Kansas, South Carolina, Alaska, Alabama and Texas are favoured to fall into Republican hands. Democrats meanwhile are tipped to win the races in Arizona, Michigan and Colorado. The remaining races are significantly less competitive and unlikely to alter the Senate’s balance of power.
Here’s what you need to know about the most competitive Senate races:
The Toss Ups
Iowa
Republican incumbent Joni Ernst was already having trouble fending off a significant challenge from Democrat Thresea Greenfield when she drew ridicule during a debate for her inability to correctly list the price of soybeans, raising eyebrows in this agriculture-dependent state.
Georgia
Republican incumbent David Perdue is virtually tied with Democratic challenger Jon Ossoff. Furthermore, Georgia is also holding a special election for the seat held by Perdue’s fellow Republican incumbent, Kelly Loeffler. Ms Loeffler is trailing Democrat Raphael Warnock in the polls, but she’s simultaneously fending off a challenger from her own party – Doug Collins – who is unlikely to win but nonetheless splitting the Republican vote.
North Carolina
Republican incumbent Thom Tillis is struggling to fend off Democratic challenger Cal Cunningham. Tillis recently contracted the coronavirus after attending Judge Amy Coney Barrett’s Supreme Court nomination ceremony at the White House. And Mr Cunningham has refused to comment on allegations that he engaged in a second extramarital affair.
Montana
Governor Steve Bullock, who unsuccessfully campaigned to win the Democratic presidential primary, is gaining ground on Republican incumbent Steve Daines.
Maine
Despite her reputation as a centrist, Republican incumbent Susan Collins is losing traction among Maine voters and falling behind Democratic challenger Sara Gideon in the polls. Gideon has criticised Collins for voting to confirm Supreme Court Justice Brett Kavanaugh, who faces allegations of sexual assault. But Collins has also vowed to vote against Mr Trump’s current Supreme Court nominee, Judge Amy Coney Barrett, if Republicans hold the vote ahead of the election.
Republicans tipping the balance
Kansas
Democrat Barbara Bollier was a life-long Republican until she switched parties in 2018 in response to the party’s rightward shift. Ms Bollier is facing off against Republican Roger Marshall, who currently occupies a seat in the House.
South Carolina
Republican incumbent Lindsey Graham, a former centrist turned staunch ally of Mr Trump, is facing his first competitive Senate race since he won the seat in 2002. Democratic challenger Jaime Harrison raised $57 million for his campaign between July and September of this year – the largest Senate fundraising haul in US history.
Alaska
Republican incumbent Dan Sullivan is favoured to fend off a challenge from Al Gross, an independent who won Alaska’s Senate Democratic primary. Mr Gross has aired ads stating that he once killed a grizzly bear in self-defence.
Alabama
Democratic incumbent Doug Jones faces an uphill battle against Tommy Tuberville, a former American football coach. Jones narrowly won his seat in a 2017 special election against Roy Moore, an alleged child molester.
Texas
Republican incumbent John Cornyn has started to distance himself from Mr Trump in recent weeks, claiming that he privately aired disagreements with the president over border security, trade and the budget deficit despite his public support for the White House’s policies. He is still favoured to prevail over Democratic challenger MJ Hegar.
Democrats tipping the balance
Arizona
Republican incumbent Martha McSally is trailing in the polls against Democrat Mark Kelly. Ms McSally was appointed to the late John McCain’s seat last year after losing a 2018 election for the state’s other Senate seat. Mr Kelly is a former astronaut and the husband of Gabrielle Giffords, a former House member who resigned after she was shot in the head.
Michigan
While Democratic incumbent Gary Peters is still favoured to win this race, Republican challenger John James has come within striking distance in the polls in recent weeks. Both candidates in this key swing state are hoping to convince enough supporters of Mr Trump and Mr Biden to vote across party lines on their ballots.
Colorado
Republican incumbent Cory Gardner is trailing behind challenger John Hickenlooper, the state’s former governor who unsuccessfully campaigned in the Democratic presidential primary
