John Bessler was at an Iowa Democratic Party dinner in Des Moines in early November when his wife's presidential campaign got word that a local school board candidate in Council Bluffs needed a cadre of campaign door-knockers the next day.

Bessler, a law professor and the husband of Minnesota U.S. Sen. Amy Klobuchar, was there the next morning at 9 to join the team of volunteers.

"I think he hit about 50 doors for us," said Iowa labor activist Jeff Shudak, the school board candidate's brother.

Democratic presidential rivals Pete Buttigieg and Elizabeth Warren also sent volunteers, Shudak said. But only the Klobuchar team sent the spouse.

"That's walking the walk," said Shudak, who is now backing Klobuchar's presidential bid.

Like any national politician, Klobuchar relies on a core network of family and close advisers to keep up with the demands of the job. In a presidential campaign, those demands multiply. Bessler, an unassuming professor, author and expert on the death penalty, has generally kept out of the public eye in Minnesota, where he grew up.

But he's emerging as a familiar face in early voting states such as Iowa and New Hampshire, becoming something of a secret weapon in his wife's campaign.

"There's a frenzy around any candidate for president at this stage," said Jay Kahn, a New Hampshire state senator who endorsed Klobuchar on New Year's Eve. Kahn's endorsement came after three long conversations with Bessler, followed by a couple with Klobuchar to close the deal. "There's so many people that want to share a moment with the candidate," Kahn said. "John was able to step back and engage in a little deeper conversation."

The 2020 Democratic primary includes a very small group of men who, if their candidate-spouse were elected, would become the first "First Gentleman" in U.S. history. One, Chasten Buttigieg, has become a political celebrity in his own right, amassing more than 390,000 Twitter followers.

Bessler doesn't have a Twitter account. But with less than a month before Iowa's first-in-the-nation caucuses — and the prospect of a Senate impeachment trial that could strand Klobuchar in Washington for weeks — he is poised to become an even more important proxy as his wife struggles to break into the top rank of contenders.

Bessler's not one to get too worked up, no matter the pressure.

"We're not sure yet how that's going to shape up," he said in an interview. Even as the rigors of the campaign intensify, he's preparing for a spring semester teaching three law school classes: two courses at the University of Baltimore School of Law, where he's a faculty member, and a seminar on the death penalty at Georgetown Law, where he's an adjunct professor.

While the schedule is less than ideal, the pressures are relatable.

"Got to work. We're very middle class, you know? And we have to pay for our apartment in D.C. and our house in Minnesota," said Bessler, deftly echoing one of his wife's frequent stump speech lines, that she doesn't "come from money."

Bessler's roots are even more humble than those of his wife, one of two children of a well-known former Star Tribune columnist and a schoolteacher. Bessler, one of six sons of a college biology professor and a stay-at-home mom, was a young child when his parents moved the family from Indiana to Mankato so his father could take a teaching job. Marilyn and Bill Bessler, now retired, still live in Mankato.

"He has a humbleness born of growing up in a trailer with five brothers," Klobuchar said of her husband. "He has worked his way through everything he ever did. He graduated from high school early, and he graduated from college early."

Thought about politics

Bessler, 52, is more than seven years younger than Klobuchar, who's 59. They met at a Minneapolis bar in 1991, part of a small group of lawyers who gathered there after an event at the University of Minnesota's Humphrey School of Public Affairs. Klobuchar thought he was older, she said, because he was already working at the big Minneapolis firm then known as Faegre & Benson (he was the youngest associate in the firm's history).

"They were definitely a couple that was going somewhere," recalled Jim Sheehy, a Minneapolis attorney who claims credit for introducing the two that night.

In 1992, Bessler proposed to Klobuchar in a nonfiction aisle at St. Paul's now-defunct Hungry Mind Bookstore. He had chosen Abraham Lincoln's birthday to pop the question.

"Valentine's Day seemed too cliché," Bessler said. Klobuchar recalled their honey­moon in Switzerland: "I was 33, and he still qualified for the Eurail youth pass," she said.

Teasing her husband is frequently part of Klobuchar's campaign trail patter. Last summer at a veterans' home in Marshalltown, Iowa, Klobuchar and Bessler along with a retinue of campaign aides and local officials were about to start a tour when an alarm went off in the lobby.

"My husband didn't cause this, did he?" Klobuchar asked in a stage whisper. As the tour wrapped up a little while later, the group passed some elaborate planters at the front of the building.

"John, maybe you can get some ideas for our front yard," Klobuchar said.

In her memoir, "The Senator Next Door," Klobuchar writes that some of Bessler's high school classmates at Loyola Catholic School in Mankato thought he would go into politics someday. "One of them came up to me at some event, years ago," Klobuchar recalled. "And she said, 'I thought John would be the one.' I felt bad about it, actually."

Asked whether he ever harbored his own political ambitions, Bessler thought back to 1994, when Klobuchar first mulled a run for Hennepin County attorney (she finally ran and won in 1998).

"I had just finished law school," he said. "She was in a position to run for office. I was not."

In the years since, he said, he's worked on his wife's various campaigns, providing feedback on speeches and marching in parades. He researches and writes briefing documents on issues on which he has expertise. At home, he took on a heavy share of parenting duties for their daughter, Abigail, born in 1995 and also a regular on the presidential campaign trail.

After practicing law in Minneapolis for more than a decade, Bessler shifted into teaching when the family relocated to the Washington, D.C., area following Klobuchar's 2006 election to the Senate.

"He travels in these elite circles, but he's also here in Baltimore every week rolling up his sleeves and getting it done for our students," said Ronald Weich, dean of the University of Baltimore law school.

Critic of death penalty

Bessler has written or edited 10 books. Half were about the death penalty, which he considers a form of torture that he'd like to see abolished.

"Look around the world at countries like Mongolia and Rwanda that have gotten rid of the death penalty," Bessler said. "And if you look at who still has the death penalty around the world — Iran, China, Iraq, Yemen — it's kind of a rogue's gallery of human rights abuses."

But his writing interests have ranged widely. In several recent volumes, he tackled the European Enlightenment roots of the American legal system. In 2007, he published a book on the craft of writing itself.

Promoting the art of good writing is something Bessler envisions as a potential cause to champion were he to actually become the president's husband. Human rights, informed by his death penalty work, also could be a focus, he said.

"But," Bessler was quick to add, "it'd be a bit presumptuous to think much about that when we're still in the midst of all this."

The rigors of a presidential campaign typically keep Bessler and Klobuchar apart all but one or two nights a week; his last anniversary gift was a tweet from his wife. On the rare night off, he said, they might watch a movie or a TV show.

"Amy likes 'Madam Secretary,' " Bessler said, referring to the CBS drama series about the first female U.S. president. "That's one of her favorite shows. I'll occasionally sit through one of those with her."