Vice President Kamala Harris is the presumptive 2024 Democratic nominee for president, and one of the issues that has come up in the days since she was endorsed by President Biden is her leadership dealing with the migrant crisis at the southern border. But what is her role, and what is her record?

Migrant crossings at the southern border, which had been increasing in the last months of the Trump administration, skyrocketed after Biden entered office. Biden also rolled back a number of Trump-era initiatives and attempted to place a moratorium on deportations. With numbers rising quickly, Biden told reporters that Harris would be put in charge of tackling root causes, issues like climate change, poverty and violence the administration believes was driving migrants north.

"There’s about five other major things she’s handling, but I’ve asked her, the VP, today — because she’s the most qualified person to do it — to lead our efforts with Mexico and the Northern Triangle and the countries that help — are going to need help in stemming the movement of so many folks, stemming the migration to our southern border," he said.

It quickly led to Harris being dubbed by media outlets and Republicans as the "border czar." The White House rejected that title, but it has stuck with her ever since and made her a figurehead along with DHS Secretary Alejandro Mayorkas for the crisis.

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After the assignment by Biden, and with numbers skyrocketing through subsequent months to record highs, Harris immediately came under pressure to visit the border as the White House said her role was more diplomatic than related to the border directly. She instead went to Mexico and Guatemala and had a stern message for migrants that upset immigrant activists.

"Do not come. Do not come. The United States will continue to enforce our laws and secure our borders," she said. "If you come to our border, you will be turned back."

Yet the migrants did continue to arrive, and the crisis only grew in the months ahead.

An awkward moment took place during her trip to Mexico, when she asked a reporter named Maria Fernanda to ask a question during a press conference. But it was actually an activist.

"I voted for you," she said. "My question is, what would you say to these women, those mothers and also women of color on both sides of the border, farmers, many of them who I see every day as a message of hope but also as — what will you do for them in the next coming years?"

As the pressure rose for her to go to the U.S. southern border, Harris pushed back.

"You haven’t been to the border," NBC’s Lester Holt told her, after she claimed she had been to the border.

"And I haven’t been to Europe," Harris quipped.

Later that month, she went to the border in El Paso, Texas, where she received a briefing and toured a processing center while meeting with advocates and providers.

Amid the ongoing crisis, reports emerged that Harris was dissatisfied with her role in general, including the border assignment. Politico reported that the border visit was a "chaotic moment" in an office dealing with diminished trust and low morale. In a book released in 2023, an author reported she let the assignment slide.

"She let the criticism guide her," Franklin Foer wrote in "The Last Politician." "Instead of diligently sticking to the Central America assignment, she seemed to accept the conventional wisdom about it. It was a futile gig, so she let it fall to the side, missing an opportunity to grind her way to a meaningful achievement."

Harris was one of the members of the administration who fueled a since-debunked narrative about migrants being whipped by Border Patrol agents in the Del Rio Sector.

"What I saw depicted about those individuals on horseback treating human beings the way they were was horrible," Harris told reporters. "And I fully support what is happening right now, which is a thorough investigation into exactly what is going on there. But human beings should never be treated that way. And I'm deeply troubled about it. And I'll also be talking to Secretary [Alejandro] Mayorkas about it today."

A subsequent investigation faulted the agents for minor infractions but found the underlying claims migrants were whipped were not true.

Harris would largely be unseen through the rest of 2021 and 2022 on the root causes strategy, although a private sector initiative to draw investment to tackle those root causes would continue. But she would not visit the border again.

Amid continually high numbers that outpaced 2021, Harris warned that her strategy could not be expected to bring results right away.

"None of this is going to be just turning on a switch. It requires focus. It requires intention. It requires an investment over a period of time, which means, in the short point, is that you’re not going to see the benefit of it overnight because the problems didn’t occur overnight," she said in an interview.

AXIOS HIT WITH COMMUNITY NOTE AFTER CLAIMING HARRIS WAS NEVER ‘BORDER CZAR’

In June 2022, she traveled to the Summit of the Americas in Los Angeles and met with other leaders on how to handle the crisis. During that summit, she announced that $3.2 billion in commitments from private sector companies had been secured. She also doubled down on the root causes explanation for the crisis.

"First, I do believe most people don't want to leave home. They don't want to leave their grandmother. They don't want to leave the place where they worship and the community that they've always known," she said. "And so, when they do, it is usually for one of two reasons: They are fleeing harm or to stay means they simply cannot satisfy their basic needs or the needs of their family."

But 2022’s summer broke records for migrant encounters, and those numbers would worsen in 2023.

With a record summer having passed, Harris came under fire for declaring the border was secure despite the ongoing crisis and mass releases into the interior.

"The border is secure, but we also have a broken immigration system, in particular over the last four years before we came in, and it needs to be fixed," Harris said on NBC.

Harris made few appearances in 2023 relating to the border crisis, although her private investment strategy continued to bring in additional commitments from companies.

But the crisis did not stay out of the news, and 2023 broke new records for enormous amounts of migrant encounters and a number of chaotic scenes at the border.

Fiscal year 2023 broke the record for encounters with over 2.4 million, while December had nearly 250,000 encounters in a single month.

While the White House continued to reject the "border czar" narrative, Harris put her support behind a bipartisan Senate agreement to provide more funding to the border and reduce migrant crossings when they reach a certain level.

She also backed a number of executive orders by President Biden, who would implement a limit on asylum and efforts to provide a pathway to citizenship for illegal immigrants who are spouses of U.S. citizens.

CLICK HERE FOR MORE COVERAGE OF THE BORDER SECURITY CRISIS

As she began to step into the role of 2024 Democratic presidential nominee, Harris touted what her team sees as successes in the role. The project to rally private-sector investment to the region via a call to action has seen more than $5.2 billion committed since May 2021 from over 50 companies and organizations.  Additionally, officials noted the numbers of encounters from Northern Triangle countries have fallen from over 700,000 in fiscal 2021 to over 330,000 so far as of May, with four months left to go.

However, according to CBP data, during 3½ years of the Biden/Harris administration, illegal crossings of migrants from Mexico, El Salvador, Guatemala and Honduras are up 140% over Trump's first term in office and are up 34% over all eight years of Obama's two terms in office.

Harris has also promised to roll out additional solutions to the border crisis, while accusing former President Trump of scuttling efforts for reform.

"[Trump] can make up whatever lies he wants, but the fact is there’s only one candidate in this race who will fight for real solutions to help secure our nation’s border, and that’s Vice President Harris," Harris campaign spokesperson Kevin Munoz said.

Fox News' Bill Melugin contributed to this report.