WASHINGTON: Kamala Harris said Tuesday she was "proud" to tap Tim Walz as her running mate, opting for the Minnesota governor with blue-collar credentials as the partner most likely to boost her historic - and bruising - bid for the White House.

Walz had been on a vice-presidential shortlist with a string of other Democratic figures seen as broadening Harris's appeal as she sprints into the contest against Donald Trump.

Aiming to make history as the first woman president, Harris - already a trailblazer as the first female and first Black and South Asian vice president - has little time before Election Day on November 5.

"I am proud to announce that I've asked @Tim_Walz to be my running mate," she posted on X.

"As a governor, a coach, a teacher, and a veteran, he's delivered for working families like his. It's great to have him on the team."

Expectations had always been that Harris would pick a white man to balance the ticket and help win over working-class, white, male voters, a demographic that propelled Trump to victory in 2016.

Walz fits that description as a 60-year-old Midwesterner with a folksy manner, decades of military experience and a rural perspective - a gun-owning Democrat who tweets about hunting.

The onetime teacher and school sports coach flipped a Republican district to win a seat in the US House of Representatives in a state seen as light years from the coastal elites of California, Harris's home turf, or the East Coast.

At the same time, Walz will appeal to the left for championing popular Democratic policies including cannabis legalization, increasing worker protections, safeguarding abortion rights, and supporting tighter firearm restrictions.

Trump's campaign immediately branded the Minnesotan as a "dangerously liberal extremist" seeking to impose California values on the nation.

But "to characterize him as left is so unreal," Nancy Pelosi, the former House speaker who worked extensively with him in Congress, told MSNBC.

Walz "is right down the middle. He's a heartland of America Democrat."

Walz called his naming the "honor of a lifetime" and quipped it felt like "the first day of school."

He and Harris will hit the campaign trail immediately, launching an intense, five-day swing through battleground states starting Tuesday in the biggest prize, Pennsylvania.

Fresh from securing the official Democratic nomination, Harris will head to the national convention in Chicago in two weeks in total control of her party.

It has been a remarkable journey for Harris, who only entered the race last month when 81-year-old President Joe Biden withdrew, bowing to mounting concerns over his mental acuity.

In a campaign barely two weeks old, the 59-year-old former prosecutor and senator has obliterated fundraising records, attracted huge crowds and dominated social media on her way to erasing what had been Trump's growing lead in polls over Biden.

The latest presidential poll by the University of Massachusetts Amherst released Monday has Harris leading Trump nationally by three percentage points - 46 to 43 - compared to a four-point lead for Trump over Biden in January.

In the swing states that decide the Electoral College contest in US elections, Harris is neck and neck with Trump, who shocked the world with his 2016 presidential victory but was beaten by Biden in 2020.

Picking a running mate was seen as the first big test for Harris in her bid to become the country's chief executive.

Now, Harris and Walz will face the first hurdle of their ground game as they make the nationwide swing this week from Philadelphia to Wisconsin, Michigan, Arizona and Nevada.

Tropical Storm Debby has forced the postponement of a stop in battleground Georgia, and according to media reports also North Carolina.

Pennsylvania is part of the "blue wall" that carried Biden to victory in 2020, alongside Michigan and Wisconsin. That was a main reason many expected Harris to instead pick that state's governor, Josh Shapiro.

Also on the vice presidential shortlist had been former astronaut and current US Senator Mark Kelly, of Arizona, and Kentucky Governor Andy Beshear.

 - AFP