Democrats' Chances of Winning the Senate, the House and the White House in Election Clean Sweep

The Democrats have a 45 percent chance of securing a hat-trick of election victories on Tuesday—gaining control of the Senate, maintaining control of the House and Joe Biden winning the race for the White House—according to a leading bookmaker.

UK-based Betfair priced a clean sweep for Joe Biden's party at 6-5 (an implied probability of 45 percent, according to the bookmaker).

The GOP have odds of 5-1, implying a 17 percent chance of securing majorities in the Senate and House and giving Donald Trump another term as president.

Betfair spokesperson Darren Hughes said: "As well as Trump being behind Biden in the betting to win the presidential election, the Republican party could have very little to show for following the 2020 elections as the Democrats are 6-5 to claim a whitewash by winning the presidential election, House and Senate, while a hat-trick for the GOP is 5-1.

"The Republicans are keen to point out any success with the economy, but with five days to go the odds still favour a win for the Democrats."

Republicans currently enjoy a majority in the Senate, by 53 to 45, while there are two independents who caucus with the Democrats.

In order for Democrats to seize control of the Senate, they would need to gain at least four seats—earning them a majority of 51 to 49. However, if Biden wins against Trump, Democrats could still control a 50-50 split with Biden's running mate, Kamala Harris, having the deciding vote.

The Democrats currently control the House of Representatives after a "blue wave" in the 2018 midterm elections.

To take back the chamber, the GOP needs to secure at least 19 or 20 seats on November 3.

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The U.S. Capitol is shown June 5, 2003 in Washington, DC. The GOP have odds of 5-1, implying a 17 percent chance of securing majorities in the Senate and House and giving Trump another term as president. Stefan Zaklin/Getty Images

Forecasts from Decision Desk currently predict Biden has an 87.9 percent chance of winning the presidency, an 82.3 percent chance of controlling the Senate and a 98.6 percent chance of controlling the House.

The forecasting model, which draws its data from publicly available polling channels, said there was a 10.1 percent chance of a tied (50-50) chamber.

The model for the Senate has moved 1.2 percent in the Democrats favor over the last day, 0.8 percent for the Democrats over the last week, and -2.3 percent for the Republicans over the last month, Decision Desk said.

For the House, Decision Desk's model showed the polls have moved +0.1 percent for the Democrats over the last day, +0.4 percent for the Democrats over the last week but +0.3 percent for the Republican over the last month.

And for the presidency, their model has moved +0.2 percent for the Republicans over the last day, +1.2 percent for the Democrats over the last week, and +5.7 percent for the Democrats over the last month.