Brett Kavanaugh’s path to the US Supreme Court is all but assured after two senators said they will elect the conservative to the country’s highest court.

The announcements by Republican Susan Collins of Maine and Democrat Joe Manchin of West Virginia ended most of the suspense over a political battle that has transfixed the nation — though die-hard Democrats insisted on arguing through the night to a mostly empty Senate chamber.

Some of them continued raising concerns that Mr Kavanaugh would push the court further to the right, including with possible sympathetic rulings for president Donald Trump, the man who nominated him.

Supreme Court ProtestProtesters rally in front of Trump Tower against the nomination of Mr Kavanaugh (Seth Wenig/AP)

But the case against Mr Kavanaugh had long since been taken over by allegations that he sexually abused women decades ago — accusations he emphatically denies.

In the pivotal moment on Friday, Mrs Collins, perhaps the chamber’s most moderate Republican, proclaimed her support for Mr Kavanaugh at the end of a Senate floor speech that lasted nearly 45 minutes.

She told fellow senators that Christine Blasey Ford’s dramatic testimony last week describing Mr Kavanaugh’s alleged 1982 assault was “sincere, painful and compelling”.

Pictures Of The Week Photo GalleryChristine Blasey Ford testified about an assault (Win McNamee/AP)

But she said the FBI had found no corroborating evidence from witnesses whose names Ms Ford had provided.

“We will be ill-served in the long run if we abandon the presumption of innocence and fairness, tempting though it may be,” she said. “We must always remember that it is when passions are most inflamed that fairness is most in jeopardy.”

The story is expected to conclude on Saturday afternoon with a final roll call almost solidly along party lines.

That would mark an anti-climactic finale to a clash fought against the backdrop of the #MeToo movement and Mr Trump’s unyielding support of the nominee, and opposing forces that left Mr Kavanaugh’s fate in doubt for weeks.

Mr Manchin, the only remaining undeclared politician, used an emailed statement to announce his support for Mr Kavanaugh moments after Ms Collins finished talking, making him the only Democrat supporting the nominee.

He faces a competitive re-election race next month in a state which Mr Trump carried in 2016 by 42 percentage points.

Supreme Court ProtestA protester holds a gavel with a picture of Brett Kavanaugh in New York (Seth Wenig/AP)

“My heart goes out to anyone who has experienced any type of sexual assault in their life,” Mr Manchin said.

But he added that based on the FBI report, “I have found Judge Kavanaugh to be a qualified jurist who will follow the Constitution and determine cases based on the legal findings before him.”

Protesters chanted “shame” at Mr Manchin later when he talked to reporters outside his office.

Republicans control the Senate by a meagre 51-49 margin. Support from Ms Collins and Mr Manchin would give Kavanaugh at least 51 votes.

Republican Lisa Murkowski of Alaska, a fellow moderate and a friend of Ms Collins, is the only Republican who has indicated she will vote no.

She told reporters that Mr Kavanaugh is “a good man” but maybe “not the right man for the court at this time”.

When Mr Trump nominated Mr Kavanaugh in July, Democrats leapt to oppose him, saying that past statements and opinions showed he’d be a threat to the Roe v Wade case that assured the right to abortion.

They said he also seemed ready to rule for Mr Trump if federal authorities probing his 2016 campaign’s alleged connections to Russia try to pursue him in court.

Yet Mr Kavanaugh’s pathway to confirmation seemed unfettered until Ms Ford accused him of drunkenly sexually assaulting her in a locked bedroom at a 1982 high school gathering.

Two other women later emerged with sexual misconduct allegations from the 1980s.

Mr Kavanaugh foes cast him as a product of a hard-drinking, male-dominated, private school culture in Washington’s upscale Maryland suburb of Bethesda. He and his defenders asserted that his high school and college focus was on academics, sports and church.

Democrats also challenged Mr Kavanaugh’s honesty, temperament and ability to be nonpartisan after he fumed at last week’s Judiciary hearing that Democrats had launched a “search and destroy mission” against him fuelled by their hatred of Mr Trump.

Mr Kavanaugh would replace the retired Justice Anthony Kennedy, who was a swing vote on issues including abortion, campaign finance and same-sex marriage.