WASHINGTON, United States (AFP) — Brett Kavanaugh’s confirmation to the US Supreme Court appeared all but assured Friday after two key lawmakers signalled their support, in a major boost for President Donald Trump.

Senate Republican Susan Collins affirmed in a closely-watched floor speech that she will vote for the conservative jurist nominated by Trump, and moments later Democrat Joe Manchin broke ranks to announce his own backing.

Their declarations brought the number of senators publicly supporting the 53-year-old judge — who has faced accusations of sexual assault — to 51 in the 100-member chamber.

A final confirmation vote is expected Saturday afternoon.

Kavanaugh’s nomination was left teetering on the edge after university psychology professor Christine Blasey Ford claimed in harrowing testimony last week that he tried to rape her when they were high school students.

But Collins, a moderate, pro-choice lawmaker from Maine, said Kavanaugh was entitled to the “presumption of innocence” as the allegations against him lacked corroborating evidence.

While Collins acknowledged that Blasey Ford’s testimony was sincere, painful and compelling, and that the accuser is a sexual assault survivor, she added that, “I do not believe that these charges can fairly prevent Judge Kavanaugh from serving on the court.”

Immediately after the Collins speech, Manchin announced his support, calling Kavanaugh a “qualified jurist” who “will not allow the partisan nature this process took to follow him onto the court.”

Manchin faces extraordinary political pressure. He is up for re-election in West Virginia, a state Trump won overwhelmingly in 2016.

Earlier on Friday, the Senate voted 51-49 to end debate on Kavanaugh’s nomination, setting up a final showdown on Saturday.

The outcome had remained in doubt, however, after one Republican, Lisa Murkowski, defied her party and voted against moving ahead.

Trump nevertheless cheered the result of the cloture vote.

“Very proud of the US Senate for voting ‘YES’ to advance the nomination of Judge Brett Kavanaugh!” the president said on Twitter.

After Collins’s speech, White House press secretary Sarah Sanders took to Twitter to thank her “for standing by your convictions and doing the right thing,” while former president George HW Bush saluted her “political courage and class.”

If he wins confirmation, Kavanaugh — who has faced a bruising process that raised questions over his candor and partisan rhetoric, and his lifestyle as a young man — will seal a conservative majority on the nine-seat high court for years to come.

Trump took the brutal battle to a new stage earlier Friday when he dismissed female anti-Kavanaugh protesters who have cited their own experiences of sexual assault as “elevator screamers.”

The president claimed billionaire financier George Soros, a frequent target of conservatives, was behind their demonstrations.

“The very rude elevator screamers are paid professionals only looking to make Senators look bad. Don’t fall for it!” he tweeted.