With a razor-thin margin of error, Vice President Mike Pence is standing by to vote in favour of Supreme Court nominee Brett Kavanaugh should Republicans be unable to corral 51 votes to confirm the judge outright.

Republicans control the Senate 51 to 49, making Mr Pence’s involvement a potential necessity if just one GOP senator decides to vote against Mr Kavanaugh’s nomination.

As it stands, three Republican senators have signalled they are on the fence about whether to elevate Mr Kavanaugh — Senators Lisa Murkowski, Susan Collins, and Jeff Flake. Red-state Democrat Joe Manchin also voted in favour of sending Kavanaugh to a final vote, and many think he's likely to vote in favour of the judge.

Tensions are high in Washington, where the Senate voted on Friday for cloture, a procedural hurdle that sets up a final confirmation vote for Saturday.

As the Senate considers what to do, protesters have swarmed the capitol, and hundreds of anti-Kavanaugh demonstrators have been detained by police. On Thursday, protesters filled the Hart Senate Office Building, urging senators to drop Mr Kavanaugh and look to another nominee.

Mr Kavanaugh’s confirmation was thrust into controversy after Dr Christine Blasey Ford, a California university professor, came forward with accusations that the nominee had sexually assaulted him while they were both teenagers more than 30 years ago. In her Senate testimony, Dr Ford said that Mr Kavanaugh had drunkenly assaulted her at a house party while they were in high school, groping her, attempting to remove her clothes, and holding her mouth shut so she could not scream.

In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing Show all 21 1 /21 In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing WASHINGTON, DC - SEPTEMBER 04: Protesters disrupt the confirmation hearing for Supreme Court nominee Judge Brett Kavanaugh before the Senate Judiciary Committee in the Hart Senate Office Building on Capitol Hill September 4, 2018 in Washington, DC. Kavanaugh was nominated by President Donald Trump to fill the vacancy on the court left by retiring Associate Justice Anthony Kennedy. (Photo by Chip Somodevilla/Getty Images) Chip Somodevilla Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A member of Code Pink protests as US Supreme Court nominee Brett Kavanaugh arrives on the first day of his confirmation hearing in front of the US Senate on Capitol Hill in Washington DC, on September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing epa06996310 Circuit judge Brett Kavanaugh prepares to testify before his Senate confirmation hearing to be an Associate Justice of the Supreme Court of the United States in the Hart Senate Office Building in Washington, DC, USA, 04 September 2018. President Trump nominated Kavanaugh to fill the seat of retiring justice Anthony Kennedy. If confirmed, Kavanaugh would give conservatives a five-member majority in the high court. EPA/MICHAEL REYNOLDS MICHAEL REYNOLDS EPA In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing WASHINGTON, DC - SEPTEMBER 04: Protesters dressed in The Handmaid's Tale costume, protest outside the hearing room where Supreme Court nominee Judge Brett Kavanaugh will testify before the Senate Judiciary Committee during his Supreme Court confirmation hearing in the Hart Senate Office Building on Capitol Hill September 4, 2018 in Washington, DC. Kavanaugh was nominated by President Donald Trump to fill the vacancy on the court left by retiring Associate Justice Anthony Kennedy. (Photo by Win McNamee/Getty Images) Win McNamee Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protester is removed during a hearing of the Senate Judiciary Committee on the nomination of Brett Kavanaugh to the US Supreme Court September 4, 2018 in Washington, DC. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A woman stands and voices her opposition to Supreme Court nominee Brett Kavanaugh, during a Senate Judiciary Committee confirmation hearing on his nomination for Supreme Court, on Capitol Hill, Tuesday, Sept. 4, 2018, in Washington. (AP Photo/Jacquelyn Martin) Jacquelyn Martin AP In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing WASHINGTON, DC - SEPTEMBER 04: Supreme Court nominee Judge Brett Kavanaugh arrives for testimony before the Senate Judiciary Committee during his Supreme Court confirmation hearing in the Hart Senate Office Building on Capitol Hill September 4, 2018 in Washington, DC. Kavanaugh was nominated by President Donald Trump to fill the vacancy on the court left by retiring Associate Justice Anthony Kennedy. (Photo by Win McNamee/Getty Images) Win McNamee Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing WASHINGTON, DC - SEPTEMBER 04: Protesters disrupt the start of the Supreme Court nominee Judge Brett Kavanaugh's confirmation hearing before the Senate Judiciary Committee in the Hart Senate Office Building on Capitol Hill September 4, 2018 in Washington, DC. Kavanaugh was nominated by President Donald Trump to fill the vacancy on the court left by retiring Associate Justice Anthony Kennedy. (Photo by Mark Wilson/Getty Images) Mark Wilson Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protestor is carried out by security as US Supreme Court nominee Brett Kavanaugh attends the first day of his confirmation hearing in front of the US Senate on Capitol Hill in Washington DC, on September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A woman stands and voices her opposition to Supreme Court nominee Brett Kavanaugh, during a Senate Judiciary Committee confirmation hearing on his nomination for Supreme Court, on Capitol Hill, Tuesday, Sept. 4, 2018, in Washington.(AP Photo/Jacquelyn Martin) Jacquelyn Martin AP In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protestor is escorted out of the room as US Supreme Court nominee Brett Kavanaugh attends the first day of his confirmation hearing in front of the US Senate on Capitol Hill in Washington DC, on September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing U.S. Supreme Court nominee judge Brett Kavanaugh points to his daughters as his wife Ashley looks on before the start of his Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, U.S., September 4, 2018. REUTERS/Chris Wattie CHRIS WATTIE REUTERS In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A woman protests as US Supreme Court nominee Brett Kavanaugh arrives on the first day of his confirmation hearing in front of the US Senate on Capitol Hill in Washington DC, on September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing U.S. Capitol police officer lead detained protesters out of the start of U.S. Supreme Court nominee Judge Brett Kavanaugh's Senate Judiciary Committee confirmation hearing on Capitol Hill in Washington, U.S., September 4, 2018. REUTERS/Joshua Roberts JOSHUA ROBERTS REUTERS In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protester is removed during a hearing of the Senate Judiciary Committee on the nomination of Brett Kavanaugh to the US Supreme Court September 4, 2018 in Washington, DC. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protester is removed during a Senate Judiciary Committee confirmation hearing for U.S. Supreme Court nominee judge Brett Kavanaugh on Capitol Hill in Washington, U.S., September 4, 2018. REUTERS/Joshua Roberts JOSHUA ROBERTS REUTERS In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing A protester is removed during a hearing of the Senate Judiciary Committee on the nomination of Brett Kavanaugh to the US Supreme Court September 4, 2018 in Washington, DC. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by Brendan Smialowski / AFP)BRENDAN SMIALOWSKI/AFP/Getty Images BRENDAN SMIALOWSKI AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing epa06996576 A protester is removed as circuit judge Brett Kavanaugh appears before his Senate confirmation hearing to be an Associate Justice of the Supreme Court of the United States in the Hart Senate Office Building in Washington, DC, USA, 04 September 2018. President Trump nominated Kavanaugh to fill the seat of retiring justice Anthony Kennedy. If confirmed, Kavanaugh would give conservatives a five-member majority in the high court. EPA/JIM LO SCALZO JIM LO SCALZO EPA In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing epa06996814 Protesters inside the Hart Senate Office building under arrest as Brett Kavanaugh appears before his Senate confirmation hearing to be an Associate Justice of the Supreme Court of the United States in the Hart Senate Office Building in Washington, DC, USA, 04 September 2018. President Trump nominated Kavanaugh to fill the seat of retiring justice Anthony Kennedy. If confirmed, Kavanaugh would give conservatives a five-member majority in the high court. EPA/TASOS KATOPODIS TASOS KATOPODIS EPA In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing US Capitol Police arrest a protestor during the US Senate Judiciary Committee confirmation hearing for Judge Brett Kavanaugh to be an Associate Justice on the US Supreme Court, on Capitol Hill in Washington, DC, September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. Some two dozen witnesses are lined up to argue for and against confirming Kavanaugh, who could swing the nine-member high court decidedly in conservatives' favor for years to come. Democrats have mobilized heavily to prevent his approval. (Photo by SAUL LOEB / AFP)SAUL LOEB/AFP/Getty Images SAUL LOEB AFP/Getty Images In pictures: Chaos and fury at Brett Kavanaugh's confirmation hearing US Capitol Police arrest a protestor during the US Senate Judiciary Committee confirmation hearing for Judge Brett Kavanaugh to be an Associate Justice on the US Supreme Court, on Capitol Hill in Washington, DC, September 4, 2018. - President Donald Trump's newest Supreme Court nominee Brett Kavanaugh is expected to face punishing questioning from Democrats this week over his endorsement of presidential immunity and his opposition to abortion. (Photo by SAUL LOEB / AFP)SAUL LOEB/AFP/Getty Images SAUL LOEB AFP/Getty Images

She said that she is absolutely certain Mr Kavanaugh was the man who assaulted her. Mr Kavanaugh has denied all allegations of sexual misconduct that have been made against him — including those from his second accuser, Deborah Ramirez, who has alleged that Mr Kavanaugh forced her to touch his penis against her will during a party at Yale University, where they both attended.

Mr Flake, one of the potential swing votes in Mr Kavanaugh’s nomination, played an important role in forcing the Senate to follow up on those allegations. While he voted in favour of sending Mr Kavanaugh’s nomination to the full Senate from the Judiciary Committee, he also urged an FBI investigation into the allegations.