When U.S. Vice President Kamala Harris interviewed Tim Walz to be her running mate for the Democratic presidential ticket, the Minnesota governor asked her, "How can I help?," two sources close to the process said.

His primary focus on supporting her - rather than asking how much power he would have in the role - was a big point in his favor, they said.

In the weeks since, Walz has tried to burnish Harris' image on the campaign trail, lauding a woman derided by her Republican rival Donald Trump and some of his supporters for her ready laugh for "bringing back the joy" to U.S. politics.

Supportive Democrats say he is a model of masculinity for modern America, a man comfortable reporting to a woman, capable of using his 'white privilege' to boost women of color and promote reproductive rights while also enjoying hunting, fishing and fixing cars.

Republicans have challenged his military record, economic policies, and support of left-leaning social movements and ideas, including on women and LGBTQ issues. After Harris chose Walz, Trump's senior adviser Stephen Miller nicknamed him "Tampon Tim" on X, mocking a law Walz signed as governor that requires schools to supply pads, tampons or other products for "all menstruating students" in restrooms, language meant to include trans students.

Asked about the role of Walz as Harris' supporter, Trump campaign spokesperson Karoline Leavitt said, "Walz is obsessed with spreading California's dangerously liberal agenda far and wide."

But Walz's support of women, and particularly a Black woman, is part of his appeal to the political left during an election when abortion rights are front and center and polls show a widening gender gap, with women, especially younger ones, embracing the Democratic Party, Democratic strategists say.

"He's doing masculinity the right way," said Cameron Landin, 20, a delegate from Georgia who saw Walz at a Hispanic Caucus meeting on Monday. "He is playing a supportive role to Vice President Harris, to the whole party, by bringing in energy, while not necessarily trying to take over and dominate," he added.

"She's Gladys Knight and he's the Pip," said Sheletta Brundidge, a Minnesota podcaster and newspaper columnist, speaking of the 1950s soul group that featured a frontwoman and male backup singers. "He will clap for her and that's something Black women have not gotten in America in a million ... years."

On Wednesday, as he accepted the Democratic Party's nomination, Walz paused for a moment to take it all in and then said: "Thank you, first of all, to Vice President Harris. Thanks for putting your trust in me, and for inviting me to be part of this incredible campaign."

He went on to outline the policies that Harris would pursue if elected, ranging from tax cuts for middle class families to lower drug prices and safeguarding personal freedoms, repeating Harris' name.

Walz's apparent unfettered support of Harris may need some adjusting if she becomes the first woman in the White House, some historians warn.

Successfully filling the position also demands "somebody who can walk into the Oval Office and tell the president that she or he is wrong," said Joel Goldstein, a professor emeritus at the Saint Louis University School of Law, who has written two books on the vice presidency.

Poll appeal

Walz's persona is often contrasted to that of his Republican rival for the vice presidency, Ohio Senator JD Vance, who in 2021 said the U.S. was being run by "a bunch of childless cat ladies," referring to Harris and other Democrats.

"How does it make any sense that we've turned our country over to people who don't really have a direct stake in it?," he asked, triggering a social media backlash from people without children and others.

A Quinnipiac University poll of voters in battleground state Pennsylvania showed 59% of Harris supporters were more enthusiastic about the ticket after she picked Walz as her running mate, compared to 43% for Trump supporters and Vance. The poll did not give a gender breakdown.

Surveys consistently show women both register to vote and show up more reliably at the polls than men, with over 68% of eligible women saying they voted in the 2020 presidential election, compared to 65% of eligible men, according to the Center for American Women and Politics at Rutgers University.

Harris had a 15-point lead over Trump among likely female voters (55% to 40%) in the last New York Times/Siena College poll in four other swing states - Arizona, Nevada, Georgia and North Carolina. Trump had a similar lead among men.

Some men say Walz - who at 60 is around six months older than Harris - is less an evolution than a return to the norm.

"It's much more of a tradition model of American masculinity which isn't the showy hyper-performative idea of these MAGAs who photoshop Donald Trump on a ripped guy with an eight-pack and worship it," said Rick Wilson, a Republican-turned-anti-Trump political strategist who cofounded the Lincoln Project.

During a campaign event in Nevada last week, Walz drew loud applause for pointing out his state and Nevada have something important in common - both the senators in each state are women. Then he spoke warmly about Harris, literally bowed as he introduced her, and got out of the way.

Democratic Wisconsin Governor Tony Evers said Walz is modeling behavior that he thinks will become increasingly commonplace.

"We can be wingmen and real men too," he told Reuters at a breakfast for Wisconsin delegates on Monday.