The night before, the retiring Arizona Republican had gotten their hopes up -- seeming torn on whether to support confirmation of Brett Kavanaugh's Supreme Court nomination after a gut-wrenching day in the Senate Judiciary Committee. But on Friday morning, he issued a statement saying he would back Kavanaugh, after all.

"Oh f***," Sen. Chris Coons said after learning how his friend would vote. The Delaware Democrat became emotional, going silent for several seconds. "We each make choices for our own reasons," he said. "I'm struggling, I'm sorry."

Then Flake got on an elevator, and everything changed.

Flake is a sharp critic of President Donald Trump's demeanor who is retiring rather than running for re-election in a party where Trump is now the center of gravity. He is nonetheless a conservative who almost always votes with the GOP majority. However, on Friday he made his boldest break yet with Trump -- throwing Kavanaugh's confirmation into chaos and bending the Senate to his will.

Minutes after he released his statement saying he would support Kavanaugh, the morning's second key moment involving Flake occurred.

Stopped at the elevator

On the way to the Judiciary Committee's meeting to advance Trump's Supreme Court nominee to the full Senate floor, Flake was involved in a dramatic confrontation when two female protesters, Ana Maria Archila and Maria Gallagher, blocked his elevator door.

"You have children in your family," Archila told him. "Think about them. I have two children"

"I was sexually assaulted and nobody believed me," Gallagher said. Through tears, she pleaded, "Don't look away from me. Look at me and tell me that it doesn't matter what happened to me."

Head bowed, Flake nodded at the women and told them "thank you." He didn't respond directly.

Hours later, inside the committee room, came the day's third key moment.

Flake tapped Coons on the shoulder, and the two retreated to a private anteroom. It set off an hour of frantic behind-the-scenes negotiations, as questions about whether Flake had changed his mind hovered.

When Flake emerged, he dropped a bombshell that would throw Kavanaugh's confirmation into chaos: He'd vote to advance him Friday -- but wanted a weeklong FBI investigation into the sexual assault allegations he faces. Otherwise, Flake, a key swing vote, said he would oppose Kavanaugh on the Senate floor.

It was a stunning move that other Senate moderates quickly backed, forcing Senate Majority Leader Mitch McConnell's hand and leading Trump to agree to order the FBI probe.

For Flake, it was also a remarkable show of force from a senator who has become a pariah to his party's base, and who is just three months from leaving office. Skeptical Democratic activists still believe Flake will ultimately vote to confirm Kavanaugh, barring the FBI uncovering new information. But Trump's Supreme Court nominee's fate is now much less certain than it appeared Friday morning.

A clash more than two years in the making

Asked by reporters later what changed his mind, Flake said he couldn't pinpoint the reason -- but that he'd had sleepless nights.

He said it has been "remarkable over the past week" how many people saw Ford make her allegation against Kavanaugh publicly "and were emboldened to come out and say what happened to them. I've heard from friends, close friends, and I had no idea."

"I wanted to support him. I'm a conservative, he's a conservative judge. But I want a process we can be proud of," Flake said of Kavanaugh. "And I think the country needs to be behind it. And we need a more bipartisan process. That's why this is important."

A clash between Flake and Trump -- fought over a Supreme Court nominee -- is more than two years in the making.

In 2016, Flake did not support Trump when he was the GOP's presidential nominee. At one point in the campaign, Trump told Arizona allies that he would spend $10 million of his own money to oust Flake in his 2018 primary. Then, in 2017, as Trump was actively involved in attempting to recruit a primary challenger against Flake.

Rather than running what was all but certain to be a losing race, Flake opted to retire -- and announced he was writing a book critical of the direction Trump is taking the country.

A conservative who made his name challenging earmarks in the House, Flake then began challenging Trump on issues like free trade -- which the Republican Party has traditionally supported.

In January, Flake took to the Senate floor to lambast Trump for his attacks on the media, blaming the President for "the daily disassembling of our democratic institutions."

Flake's legacy and future

Flake was close to Arizona Sen. John McCain, who famously cast the deciding vote against repealing Obamacare last year. McCain's death a month ago left the Senate without its most authoritative voice to counter Trump's influence.

As a member of the Senate Judiciary Committee -- where Republicans had 11 votes to Democrats' 10 -- Flake was the only potential swing vote on the panel.

On Thursday, in a hearing scheduled to air a sexual assault allegation against Kavanaugh, California professor Christine Blasey Ford told the committee she'd feared he would rape her at a party when they were both teenagers. Kavanaugh insisted he was innocent.

Kavanaugh, in clashes with Democratic senators, said that he liked beer as a teenager and does today, too. Flake, a mild-mannered Mormon, doesn't drink.

"In the end, there is likely to be as much doubt as certainty going out of this room today," Flake said as the hearing ended Thursday night.

Friday morning, Flake was certain he'd vote for Kavanaugh -- and then he changed course.

As the Kavanaugh drama plays out over the next week, Flake -- a potential Trump 2020 primary challenger -- will travel Monday to a key early voting presidential primary state. He'll be at Saint Anselm's New Hampshire Institute of Politics to deliver a speech titled "After the Deluge: A Rejection of Destructive Politics and a Return to Principle."