The name of Minnesota Gov. Tim Walz began surfacing on lists of possible running mates for Vice President Kamala Harris almost immediately after President Joe Biden withdrew from the presidential race in late July.

However, his name was near the bottom of a list of nearly a dozen potential running mates. As could only happen in a condensed, unprecedented whirlwind of a running mate selection process, Walz shot to the top of the list through a combination of accomplishments, loyalty to both Biden and Harris during several high-profile media appearances and good chemistry with Harris.

“There were 11 candidates we started with and I’m not sure we would have put [Walz] in the top tier,” says former U.S. Attorney General Eric Holder, one of the key people Harris tasked with leading the selection committee. That changed dramatically in the following two weeks.

Walz was on a long list of potential candidates that included many with higher national profiles from important swing states, like Gov. Josh Shapiro of Pennsylvania, Sen. Mark Kelly of Arizona and Transportation Secretary Pete Buttigieg, a former presidential candidate. All of them and several others fell out of favor for various reasons, while Walz steadily rose from the “long” list to the “short”  list.

“It’s hard to pick what is the one thing that made one person be successful and the other not,” Holder told 5 EYEWITNESS NEWS in an interview last month while he was campaigning for Harris and Walz in Minnesota. “But I can say what he did as governor I thought was very significant. Very impressive.” Holder mentioned Minnesota legislation Walz signed into law, including free breakfast and lunch for every student, protecting reproductive rights and a new paid family and medical leave program.

Holder himself did a deep dive into the way Walz interacted with the media as chairman of the Democratic Governor’s Association and in network and local television appearances.

“As part of the process, the vetting process, I looked at almost every YouTube he’s ever been on,” Holder said. “Everything we could ever find about his media interactions and he’s a genuine nice guy. He’s got that Minnesota Nice thing.” Holder says as someone who grew up in the Bronx in New York City, he found Walz refreshing.

Walz and his family also had to withstand a rigorous and invasive background check. “The team, 12 to 15 lawyers, on the team that was looking at him, looking at his family, looking at their e-mails. Looking at their texts. We were all impressed by that,” Holder says.

If there was one moment that might have clinched the running mate selection for Walz, Holder says it might have been his one-on-one interview with Harris at the vice president’s residence in Washington, D.C., on Sunday, Aug. 4 — two days before she made her final decision. It all came down to chemistry.

“There was a chemistry that I saw, I actually saw that happen with Kamala Harris and with Tim Walz,” Holder says. “So it was a combination, I think, of accomplishments and chemistry that propelled him to the number two spot on the ticket.”

Despite some occasional misstatements and missteps on the campaign trail, Holder says Walz has performed as they hoped he would. “It’s fair to look at what politicians say, but I think you also have to put it in context,” Holder said. “How big was the misstatement? If it is a misstatement, does the person acknowledge that it was and say, ‘Maybe I should be more precise?’ I think that’s what he’s done whenever there has been a problem with something he has said.”

We’ll find out soon how the Walz selection impacted the election, especially as we watch for results to come in from battleground states Pennsylvania and Arizona, the home states of two other potential running mates.