"Amy! Amy! Amy!"

It was a bittersweet moment for the Minnesota senator, though -- for the rally was for Joe Biden , and the crowd was saying her name after she ended her own bid for the presidency and endorsed her formal rival.

It was only a few steps to get to the center of that stage, but the journey to this moment, accelerated in the hours before it took place, began weeks ago.

Senior aides told CNN after her sixth-place finish in the Nevada caucuses, Klobuchar began thinking about ending her own campaign to consolidate support around another candidate. Who that candidate would be did not become clear until a week later, when Biden resoundingly won South Carolina 's primary.

Klobuchar, for her part, again notched a sixth-place finish in the Palmetto State.

Publicly, though, Klobuchar showed little sign of pulling out. After her disappointing finish in Nevada, she declared at her South Carolina primary watch party, "We have exceeded expectations. A lot of people didn't even think I would still be standing at this point."

The Minnesota senator had a surprise third-place finish in New Hampshire to thank, where a strong debate performance led to her surging at the polls. But she proved unable to replicate that in the states that followed.

The leadup

Protestors take over the stage before the start of a rally for Klobuchar on March 1 in St. Louis Park, Minnesota.

In the weeks leading up to the end of her bid, Klobuchar's campaign continued to build out its Super Tuesday infrastructure, hiring staff in Colorado and North Carolina. Her campaign poured $4.7 million into advertisements, topped only by the Michael Bloomberg, Bernie Sanders and Tom Steyer campaigns (Steyer also ended his bid after a disappointing finish in South Carolina).

The campaign also said it was hiring staff in March 10 primary states.

But among Klobuchar's most senior advisers, the exit plan loomed.

Serious conversations with staff about how she would actually end the campaign did not begin until Sunday morning, a Klobuchar adviser told CNN, when Klobuchar first had a conversation with her campaign manager and longtime aide, Justin Buoen, about the prospect of ending the run.

Those conversation continued throughout Sunday and grew to include other top aides.

What aides would not elaborate on is the impact that former South Bend, Indiana, Mayor Pete Buttigieg's withdrawal from the primary race Sunday night had on Klobuchar's timing.

As Buttigieg delivered his exit speech in South Bend, leaning heavily on party unity, a chaotic scene was unfolding inside a high school gym in St. Louis Park, Minnesota. Protesters had taken over the stage where Klobuchar was set to hold a rally.

Family members of Myon Burrell -- a Minnesota teenager who was sentenced to life in prison under then-Hennepin County Attorney Klobuchar for murder -- along with protesters affiliated with the Racial Justice Network, Minneapolis NAACP and others filled the stage, chanting "Free Myon" and "Black Lives Matter."

The image was striking. At one point, Klobuchar supporters holding "Amy for America" signs stood on chairs directly across from stage shouting "Amy, Amy," to shout down the protesters, who responded with their own chants.

After a brief pause, a majority of the crowd joined in the effort to drown out the sound of the protesters. It briefly worked, but eventually, the Klobuchar campaign announced the rally was canceled. The campaign says the protesters had rejected a meeting with Klobuchar.

A chaotic morning in Utah

Klobuchar speaks at a campaign rally in Salt Lake City on Monday, March 2, 2020. She dropped out of the presidential race shortly after the event.

After that disastrous night for the Klobuchar campaign, the early morning rally in Salt Lake City, Utah, moved forward as scheduled.

But once Klobuchar stepped on stage, the mood stood in stark contrast to her rallies just a day earlier. The senator, known for delivering her campaign stump speech with gusto -- driven by her hardcore hitting-the-pavement, no-days-off energy -- appeared to go through the motions. She remarked on the gravity of the moment, the day before Super Tuesday.

"The sun is shining and you guys are at a rally at 8:30, this is what it's like on Super Tuesday when you got a lot of places to go." Both she and the crowd of roughly 100 people seemed almost solemn. She talked about her place in the popular vote getting totals: She was once third overall, but had now dropped to fifth -- a decline that could be felt in her voice.

She ended her stump by asking the audience for help.

"We want a president for all of America, not just some of America," she said.

Photos: Former presidential candidate Amy Klobuchar Photos: Former presidential candidate Amy Klobuchar US Sen. Amy Klobuchar poses for a portrait in Washington in January 2019. She has been in Congress since 2007. Hide Caption 1 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar was born in Plymouth, Minnesota, in 1960. Her mother, Rose, was a teacher, and her father, Jim, was a columnist for the Star Tribune, Minnesota's largest newspaper. Hide Caption 2 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar's first-grade photo, which she posted on Twitter in 2016. Hide Caption 3 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar was magna cum laude at Yale University, earning a bachelor's degree in political science. During college, she worked as an intern for Vice President Walter Mondale. In 1985, Klobuchar earned a law degree from the University of Chicago Law School. Hide Caption 4 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar married attorney and professor John Bessler in 1993. Hide Caption 5 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar holds her daughter, Abigail, in 1995. At the time, Klobuchar was a partner at a Minneapolis law firm. Hide Caption 6 of 37 Photos: Former presidential candidate Amy Klobuchar In 1998, Klobuchar was elected as the attorney of Minnesota's Hennepin County, which includes Minneapolis. She held that position until running for the US Senate. Hide Caption 7 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar celebrates with her husband and daughter after she was elected to the Senate in November 2006. Klobuchar won 58% of the vote to become the state's first-ever female senator. Hide Caption 8 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar participates in a ceremonial swearing-in with Vice President Dick Cheney in January 2007. Hide Caption 9 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar holds a toy train with lead paint as she testifies before a Senate subcommittee about toy safety standards in September 2007. Hide Caption 10 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar and Minnesota Gov. Tim Pawlenty survey homes that were destroyed by a storm in Hugo, Minnesota, in May 2008. Hide Caption 11 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar test-drives an electric vehicle to the US Capitol in June 2008. Hide Caption 12 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar talks on her cell phone as she rides the Capitol subway in July 2008. Hide Caption 13 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar, fifth from left, joins other female senators on stage at the Democratic National Convention in August 2008. Hide Caption 14 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar shows off her shoes to the press as she attends a White House dinner for German Chancellor Angela Merkel in June 2011. Hide Caption 15 of 37 Photos: Former presidential candidate Amy Klobuchar In March 2013, Klobuchar and US Sen. Al Franken attend a Senate hearing about a measure that would reinstate a ban on assault weapons. Hide Caption 16 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar gets on an elevator on Capitol Hill in October 2013. Hide Caption 17 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar delivers a keynote address to the BlueGreen Alliance Foundation's "Good Jobs, Green Jobs" conference in February 2014. Hide Caption 18 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar listens as Federal Reserve Chairwoman Janet Yellen testifies during a Senate hearing in May 2014. Hide Caption 19 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar, right, is joined by other female senators as she testifies during a Senate subcommittee hearing about violence and discrimination against women. Hide Caption 20 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar walks through Statuary Hall on her way back to the Senate following a joint meeting of Congress in April 2015. Hide Caption 21 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar appears on television during a hearing about the avian flu in July 2015. Hide Caption 22 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar and several of her Senate colleagues attend a photo shoot for National Seersucker Day in June 2016. Hide Caption 23 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar speaks at the Democratic National Convention in July 2016. Hide Caption 24 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar, right, talks with Sen. Debbie Stabenow in a Capitol Hill hallway in November 2016. Hide Caption 25 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar, in the lime-green jacket, joins two other US senators as they pose with Ukrainian service members in December 2016. To the right of Klobuchar are US Sen. John McCain, Ukrainian President Petro Poroshenko and US Sen. Lindsey Graham. Hide Caption 26 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar helps count Electoral College votes during a joint session of Congress in January 2016. Hide Caption 27 of 37 Photos: Former presidential candidate Amy Klobuchar During the inauguration of President Donald Trump, Klobuchar takes a selfie with, from left, US Sens. Chris Van Hollen, John McCain and Bernie Sanders. Hide Caption 28 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar and other members of the Senate Judiciary Committee attend a hearing about Supreme Court nominee Brett Kavanaugh in September 2018. Hide Caption 29 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar is joined by her husband and daughter as Vice President Mike Pence administers the Senate oath of office in January 2019. Klobuchar was just starting her third term in office. Hide Caption 30 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar, left, takes a photo with US Sen. Tammy Baldwin, center, and US Rep. Ilhan Omar before the State of the Union address in February 2019. Hide Caption 31 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar announces her presidential bid on a snowy day in Minneapolis in February 2019. Hide Caption 32 of 37 Photos: Former presidential candidate Amy Klobuchar A person sits with Klobuchar's memoir during a Klobuchar campaign stop in Albia, Iowa, in February 2019. Hide Caption 33 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar gestures during the first Democratic debates in June 2019. Hide Caption 34 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar speaks during an event in Hanover, New Hampshire, in February 2020. She finished third in the New Hampshire primary. It was her highest finish of the campaign. Hide Caption 35 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar endorses former Vice President Joe Biden in March 2020. Hide Caption 36 of 37 Photos: Former presidential candidate Amy Klobuchar Klobuchar pays her respects to George Floyd before a memorial service in Minneapolis in June 2020. Hide Caption 37 of 37

Klobuchar then told the crowd she had to hit the road, skipping her typical photo line.

She placed the mic down, grabbed a piece of paper off a stool onstage and walked off with a last wave goodbye.

As the crowd spilled out, the reporters embedded with her, flying on a separate charter, stayed at the venue. More than 20 minutes after Klobuchar left the stage, reporters began to worry, as the senator had another event in Denver just a few hours after the Salt Lake City rally ended. In order to make the rally, Klobuchar and the embeds needed to head to the private airport terminal.

As the clock kept ticking, reporters questioned staff, as the campaign provides transportation. They didn't get an answer. A reporter tweeted that Klobuchar canceled a morning radio hit in California's Bay Area -- just as Buttigieg had done the day before he dropped out.

After 40 minutes, the concert hall where the Utah rally had been held flipped off the lights, leaving reporters in the dark. Campaign aides, a typically talkative bunch, went dark themselves and didn't return texts or calls.

Breaking the news

Klobuchar endorses Joe Biden at a campaign rally on Monday, March 2, 2020, in Dallas.

As the reporters stood in the dark, Klobuchar held an all-staff call. She had looked at the math and the numbers were clear, an aide told CNN.

Multiple staffers described the 10-minute call as gratifying for the team, a group of young campaign workers that operated on a shoestring budget and often did more than one job at once.

"I've been proud of you guys every step of the way. I've been so proud that this is a campaign where people have been happy," Klobuchar told her staff.

"I've been so proud that we literally almost all stuck together from the very beginning. And that is a tribute to you."

Klobuchar, who early in her campaign faced reports that she mistreated her Senate staff, ended her presidential campaign with many of the staffers who began it with her.

While the timing may have surprised some staffers, it was what she said next that was even more startling.

"I keep trying to think of what is best for our country right now. So I decided that I'm going to be endorsing Vice President Biden today," she told them.

Klobuchar saw her decision to back Biden now as the best thing she could do to unify the party, an adviser said, but there was acknowledgement inside the Klobuchar campaign that a loss in the Minnesota primary on Tuesday would embarrass the senator.

Campaign aides told CNN that their internal numbers had her ahead of Bernie Sanders in the state, but she knew the Vermont senator had significant support.

And even if she won Minnesota, the adviser said, she knew there was a bigger picture delegate math at stake.

"So, ahead of a major voting day," the adviser said, "she thought it was best to get behind Biden. And not just suspend her campaign but endorse."

After the news was shared with Klobuchar's staff, an aide began returning texts to members of the press an hour after Klobuchar left the stage in Utah.

"You ready?" the text read.

The message was plain, leaving no doubt the campaign was over.

"The Klobuchar campaign confirms the Senator is flying to Dallas to join Vice President Biden at his rally tonight where she will suspend her campaign and endorse the Vice President," it read.

Klobuchar aides characterized the withdrawal and endorsement as "a moment of unity."

"She wanted to unite the party before Super Tuesday and put our money where our mouth is with unity and endorsing," a senior aide said. The aide notably did not discuss Klobuchar's election prospects outside of Minnesota on Super Tuesday.

In Denver, where Klobuchar was scheduled to rally next, the construction of her rally stage halted. Supporters who had not seen the news over Twitter expressed dismay and sadness as staffers explained Klobuchar was leaving the race.

"I just voted for her this morning," said a woman, dejected as she was told the news. And as a staffer handed out Klobuchar T-shirts, now relics of a bygone campaign, another woman shouted.

"2024!"