WASHINGTON — The Senate on Friday advanced the Supreme Court nomination of Brett Kavanaugh, 51-49, taking a critical step to open debate before a planned final vote this weekend.

For the rest of the day, the fate of his nomination rested with two undecided senators — Republican Susan Collins of Maine and Democrat Joe Manchin of West Virginia — until Collins came to the floor Friday afternoon and announced her decision to vote in favor of Kavanaugh.

In a floor speech that spanned 40 minutes, Collins praised Kavanaugh’s judicial thinking and record and said, while discussing the sexual misconduct allegations facing him, that the “presumption of innocence and fairness do bear on my thinking and I cannot abandon them.”

“In evaluating any given claim of misconduct, we will be ill-served in the long run if we abandon the presumption of innocence, tempting it may be,” she said. “I do not believe that these charges can fairly prevent Judge Kavanaugh from serving on the court.”

Collins said that she had listened carefully to the testimony last week of Dr. Christine Blasey Ford, who has accused Kavanaugh of sexually assaulting her at a gathering of teenagers when they were in high school in the early 1980s.

“I found her testimony to be sincere, painful and compelling. I believe that she is a survivor of a sexual assault,” said Collins, who then raised questions about Ford’s claims and pointed to holes in her account.

“This is not a criminal trial,” Collins said. “Nevertheless, fairness would dictate that the claims at least should meet a threshold of more likely than not as our standard. The facts presented do not mean that Professor Ford was not sexually assaulted that night or at some other time, but they do lead me to conclude that the allegations failed to meet the more likely than not standard.”

Minutes after Collins’ speech, Manchin, who faces a tight re-election race in a state that voted overwhelmingly for President Trump in 2016, released a statement saying that he also planned to vote in favor of Kavanaugh.

“I have reservations about this vote given the serious accusations against Judge Kavanaugh and the temperament he displayed in the hearing. And my heart goes out to anyone who has experienced any type of sexual assault in their life," he said.

"However, based on all of the information I have available to me, including the recently completed 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,” Manchin said.

Sen. Lisa Murkowski, R-Alaska, who had also been considered undecided, voted against the motion to move forward Friday morning, later calling the cloture vote itself "a mistake."

"I did not come to a decision on this until walking into the floor this morning," she told reporters. "I believe that Brett Kavanaugh is a good man, I believe that he is a good man, it just may be that in my view he’s not the right man for the court at this time."

Sen. Jeff Flake, R-Ariz., who had forced a one-week delay and a new FBI background check investigation into sexual misconduct allegations involving Kavanaugh, told reporters after the cloture vote Friday that he plans to vote to confirm the nominee Saturday barring some major unforeseen development.

Asked if he thinks Kavanaugh will be confirmed, Flake said, "I think so."

Senate Majority Leader Mitch McConnell, R-Ky., told reporters that he had had lunch with GOP leaders and Collins in the senators' dining room on the first floor of the Capitol. McConnell said, "We’re heading towards a final vote tomorrow, and I’m optimistic.”

Collins would not comment, and took her salad onto the Senate floor with her.

With the procedural vote Friday, the clock began on up to 30 hours of debate. A final floor vote is expected to take place on Saturday.

Sen. Steve Daines, R-Mont., who supports Kavanaugh, will be walking his daughter down the aisle at her wedding on Saturday. If Daines' vote is needed Saturday, he said Friday he planned to take the private plane of Rep. Greg Gianforte, R-Mont. to return to Washington following the ceremony.

But with Collins, Flake and Manchin in favor of Kavanaugh, Daines’ vote may not be necessary after all.

President Donald Trump praised the vote immediately afterward. "Very proud of the U.S. Senate for voting 'YES' to advance the nomination of Judge Brett Kavanaugh!" he tweeted.

Ahead of the vote, McConnell said on the floor that there was "absolutely no corroborating evidence for these allegations” of sexual assault against Kavanaugh.

“All the Keystone Cops were on the case,” he said. “And Senate Democrats cheered them on.”

Friday morning's vote came hours after Kavanaugh said in an op-ed article published Thursday night that he might have been "too emotional" in his congressional testimony last week.

"I was very emotional last Thursday, more so than I have ever been. I might have been too emotional at times," he wrote in an article headlined, "I am an Independent, Impartial Judge," published by The Wall Street Journal.

The article was published the same day the FBI made available to senators a report on its speedy investigation into sexual misconduct allegations against Kavanaugh. Republicans said Thursday the report had vindicated him, while Democrats blasted it as incomplete.

The vote also came amid large-scale protests against Kavanaugh's nomination that have swept Capitol Hill in the last two weeks. Trump took aim Friday morning at protesters who targeted Flake last week ahead of the Senate Judiciary Committee's vote to advance Kavanaugh's nomination to the full Senate.

"The very rude elevator screamers are paid professionals only looking to make Senators look bad. Don’t fall for it!" he tweeted. "Also, look at all of the professionally made identical signs. Paid for by Soros and others. These are not signs made in the basement from love! #Troublemakers."