Presumptive Democratic nominee Kamala Harris is reportedly meeting with her top vice president contenders on Sunday to test how well they get on. At least three of the finalists—Governor Josh Shapiro of Pennsylvania, Governor Tim Walz of Minnesota, and Senator Mark Kelly of Arizona—are scheduled to meet with Vice President Harris in what is being described as a “chemistry test,” per the New York Times.

The in-person chats are the apparent last step in the weeks-long search to choose who will join Harris on her historic 2024 ticket. The campaign has said they will announce the pick ahead of Harris’s scheduled rally in Philadelphia on Tuesday. The event will mark the duo’s first combined stop before touring seven swing states in just four days, according to Politico reporting.

It’s unclear if others in the veepstakes mix—like Transportation Secretary Pete Buttigieg and Governor Andy Beshear of Kentucky—had already met with Harris or were also on the docket.

This final test is “one that Ms. Harris is expected to put considerable stock in,” the Times writes. “Aides and associates have said that she often prioritizes personal rapport with her staff and advisers.”

These more intimate meetings come after an accelerated vetting process by the Harris campaign, and information found in that process, according to one of the finalists, has been shared with the potential VPs. A kind of public vetting process has played out in media interviews, on social media, and in the halls of Congress, too.

On Friday, Philadelphia mayor Cherelle Parker’s team published a tweet and video that appeared to show that Pennsylvania’s governor, Shapiro, was the VP pick. At first, the video seemed like an accidental leak of insider information before Harris’s choice was made public. A source close to Parker quickly told the Philadelphia Inquirer that the mayor was showing her support for Shapiro, but wasn’t announcing anything conclusive.

While the campaign’s choice to hold its first full-ticket event in Philadelphia could be seen as an Easter egg, a Harris aide “cautioned against reading too much into the first city chosen for the tour,” Politico reported.

Shapiro’s position at the helm of a key 2024 battleground state has put him on top of the veepstakes race. The governor, 51, drew national attention in 2020 when, as attorney general, he handled then-President Donald Trump’s slew of election fraud lawsuits against the state. Plus, he’s got lots of experience winning tough elections—when he took the governor’s office, Shapiro made history by winning more votes than any Pennsylvania governor ever had.

His road to the ticket has also been filled with controversy.

The director of the National Women’s Defense League critiqued Shapiro’s handling of a sexual harassment complaint against his aide and said he “should have done a better job” in that situation. (A spokesperson told the Pennsylvania Capital-Star that the governor and his administration “take every allegation of discrimination and harassment extremely seriously and have robust procedures in place to thoroughly investigate all reports.”)

Shapiro’s past views and current positions on the war in Palestine have come under intense pressure from progressives. In a 1993 article he wrote while in college, Shapiro claimed that Palestinians were “too battle-minded to be able to establish a peaceful homeland of their own.” This week, he told reporters that his views have changed.

While he’s called Israeli Prime Minister Benjamin Netanyahu “one of the worst leaders of all time,” his handling of campus anti-war protests has led some progressives to worry about how he would handle the issue as the president’s close ally.

Before Walz joined public office in 2007, he was a member of the Army National Guard and a longtime school teacher and football coach. Walz’s recent uptick in national name recognition has come from conversational and blunt interviews in which the Minnesotan talks openly about his family and community. He’s spoken about his family’s use of IVF and critiqued the GOP’s attacks on reproductive care.

The Minnesota governor has been a leading advocate of calling Trump and his vice presidential pick, J.D. Vance, simply “weird.”

“We do not like what has happened, when you can’t even go to Thanksgiving dinner with your uncle because you end up in some weird fight that is unnecessary,” Walz said on MSNBC’s Morning Joe. “Well, it’s true. These guys are just weird.”

Walz is also known for his state’s universal free school meals, which he signed into law last year. In one year, from September 2023 to September 2023, 1.1 million more breakfasts and 1.1 million more lunches were served to students—a 30 percent increase.

Bernie Sanders recently put his support behind Walz. In an interview with Minnesota Public Radio on Saturday, the senator said he “had the opportunity to talk to your governor a few days ago” and was “very impressed by him.”

“So, I hope very much that the vice president elects a running mate who will speak up and take on powerful corporate interests,” Sanders continued. “And I think Tim Walz is somebody who could do that.”

When asked about Harris’s VP pick, a source close to former Speaker of the House and top move maker Nancy Pelosi told The Hill that she “is always especially fond of former House colleagues”—seemingly a hint at Walz.

While Walz’s positions on key issues have shifted over the years, he has shown an openness to rethinking his views. At one point, he had an A rating from the National Rifle Association and received their endorsement before later denouncing the gun rights organization and proposing a ban on assault weapons.

Kelly was elected in 2020 and is best known as a Navy pilot, a NASA astronaut, and the husband of former Representative Gabby Giffords—who survived an assassination attempt in 2011 that left six dead and several injured. For years before running for office himself, Kelly was used to standing alongside his wife in her governmental duties. This experience could benefit him as a running mate for Harris, who has already faced deeply misogynistic and racist attacks from the right.

While in office, Kelly has been a firm supporter of policies that would strengthen firearm safety and security measures.

“We have some of the most permissive gun laws in the world, and we have some of the highest levels of gun violence,” Kelly told Face the Nation’s Margaret Brennan in 2023. “We passed this bipartisan Safer Communities Act. It is a step in the right direction, but it’s only one step and there is more we can do.”

If Harris were to choose Kelly, it would mean a West Coast heavy ticket—though the senator is known, in part, for his firsthand experience working on immigration policy from a border state. And he has a history of support with Latino voters, a key bloc for Democrats this year.

When Arizona’s Supreme Court upheld an 1864 abortion ban, which made nearly all abortions in the state illegal and opened the door to criminalizing healthcare providers with up to five years in prison, Kelly was staunchly opposed, saying he was, “going to fight as hard as ever to restore reproductive rights.”

Some Democrats worry about what could happen should Kelly be pegged for the presidential race. A Republican could potentially win a special election in Arizona to finish Kelly’s current term, jeopardizing control in the battleground state.

The Harris campaign has said they will announce the news via a text to supporters early this week.