WASHINGTON –After the Senate moved to advance Brett Kavanaugh's confirmation Friday morning, the spotlight fell to four conflicted senators who held the fate of President Donald Trump's nominee for the Supreme Court.

The drama over a heated confirmation that has transfixed and tore apart much of the nation essentially ended when one of those four, Republican Susan Collins, of Maine, took to the Senate floor at roughly 3:45 p.m. EDT and announced her support of Kavanaugh. She ostensibly gave him the vote he needs for confirmation.

Friday started as spellbinding drama as the quartet – Collins and fellow Republicans Jeff Flake, of Arizona, and Lisa Murkowski, of Alaska, and Democrat Joe Manchin, of West Virginia – gradually began revealing how they would vote on Kavanaugh’s nomination.

At one point, Murkowski told reporters it was "the most difficult evaluation of a decision that I’ve ever had to make ... "

The tension was building even before the Senate voted 51-49 around 11 a.m. to advance the nomination 's procedural vote setting up a final vote as early as Saturday evening.

At that point, Murkowski came out against Kavanaugh while Flake said he would back him barring a last-minute surprise.

Four hours later, Collins dramatically announced on the Senate floor she would vote for confirmation, giving Trump's embattled nominee the votes he needs for confirmation and ending the suspense over his fate that held much of the country spellbound.

Minutes after Collins’ announced her support, Manchin announced his backing of the judge.

The votes of the four senators are crucial because Republicans control the Senate by a razor-thin 51-49 margin and can afford only one defection. If the vote somehow becomes 50-50 on Saturday, Vice President Mike Pence would break the tie in favor of Kavanaugh.

Following heated confirmation hearings, explosive public protests and a last-minute FBI investigation into sexual misconduct allegations, Kavanaugh's ascension to the nation's highest court came down to these four senators:

Susan Collins of Maine

Collins voted to end debate on Kavanaugh’s confirmation, paving the way for a final vote. But it wasn’t clear at the time that she would be a "yes"' for the nominee.

It looked like Collins might oppose Kavanaugh given her comments that she was "appalled" by Trump's tweet last month criticizing Christine Blasey Ford. Ford accused Kavanaugh of sexually assaulting her at a party in suburban Maryland when both were in high school 36 years ago.

Kavanaugh has vehemently denied the allegations. And Collins said an FBI report issued Thursday that found no evidence corroborating Ford's story gave her no reason to deny Kavanaugh's confirmation.

"Fairness would dictate that the claims (by Ford) at least should meet a threshold of 'more likely than not' as our standard," she said during her floor speech. "The allegations fail to meet the more likely than not standard ... Therefore, I do not believe that these charges can fairly prevent Judge Kavanaugh from serving on the court."

Jeff Flake of Arizona

Flake, who is not running for re-election, frustrated his fellow Republicans last week by forcing the GOP leadership to agree to an FBI investigation into the allegations of sexual misconduct against Kavanaugh.

Flake said he would vote against Kavanaugh if the investigation found the allegations were true or that the nominee lied during his confirmation hearing.

Initially, it was unclear whether that meant he would support Trump's nominee to the nation's highest court.

Flake later told reporters he would support confirmation unless something significant changes.

On Friday, Flake voted to end debate and advance Kavanaugh's nomination for a final vote.

Lisa Murkowski of Alaska

The Alaska senator was the only Republican Friday to vote against moving forward on Kavanaugh, calling it a “very, very difficult" decision.

While her "no" vote on the motion to end debate suggested Murkowski is inclined to oppose Kavanaugh, the senator sounded as if she was still anguished and uncertain.

"I believe that Brett Kavanaugh is a good man, I believe he is a good man," she said. "But it just may be that in my view he’s not the right man for the court at this time," she said. "This has truly been the most difficult evaluation of a decision that I’ve ever had to make and I’ve (sic) made some interesting ones in my political career.”

Republican Sen. John Thune of South Dakota, a member of the GOP leadership, said he would be "very surprised" if Murkowski switches her vote.

Joe Manchin of West Virginia

It's not a huge surprise that Manchin voted for Trump's nominee considering he's running for reelection in a state the president won by nearly 42 percentage points over Hillary Clinton in the 2016 election.

Manchin, like Collins, also has split with his party from time to time. He was the first Democrat to meet with Kavanaugh when the nominee was meeting with senators on Capitol Hill in July.

In a statement he tweeted, the West Virginia Democrat said he had "reservations about this vote given the serious allegations." But he said he will because he considers Kavanaugh a "qualified jurist who will follow the Constitution."

Contributing: Eliza Collins, Deborah Barfield Berry