In response to a question about increasing turmoil in the Middle East, Walz, the 60-year-old Democratic governor of Minnesota, criticized Trump's record on foreign policy and said "a near 80-year-old Donald Trump talking about crowd sizes" is not what is needed.

Vance, the 40-year-old Republican senator from Ohio, responded "Donald Trump actually delivered stability in the world."

Republicans and Democrats are both hoping Tuesday's matchup will demonstrate their vice-presidential candidate's ability to connect with voters in battleground states that will play a critical role in deciding the U.S. election in November.

"They will both be trying to connect with those key Midwestern voters, that's part of why each one of them was chosen," said Matthew Lebo, a specialist in U.S. politics at Western University in London, Ont.

"Thinking about especially male voters in those key Midwestern swing states: Pennsylvania, Wisconsin and Michigan."

Those states swung Republican when Trump won the 2016 election, and in 2020 they helped put President Joe Biden in the White House.

Walz has embraced his folksy, plain-spoken demeanour since he joined the ticket earlier this summer. He's leaned into his Midwestern roots and the title "Coach Walz" from his former football coach days.

The strategy has seen him garner high favourability in polls but he will be facing a formidable opponent in Vance, who has become a mainstay on cable news shows since he was announced as Trump's running mate in July.

Formerly a Trump critic, Vance was elected to the U.S. Senate in 2022 after becoming one of the former president's loudest supporters.

Before entering the political sphere, Vance rose to fame with the 2016 publication of his memoir, "Hillbilly Elegy." The Republican vice-presidential hopeful opened the debate talking about his life and struggles growing up.

Both men are expected to play on their working-class narratives during the debate to give credibility to their party's plans for the economy and inflation.

"Vance is brilliant and I'm expecting good things from him," said Alec Beck, chairman of the fifth congressional district for the Republican Party of Minnesota, at a watch party in New Hope.

"And our governor is very good on his feet, even though he's not on our team, I give the devil his due. He has a lot of skills in this area."

Political experts have said Vice-President Kamala Harris dominated the presidential debate last month by prodding Trump into tirades that strayed far from his intended goals of focusing on immigration and the economy.

Aaron Kall, the director of debate for the University of Michigan, said it's unlikely Vance will fall for the same strategy, and he expects Tuesday night's debate will lean more into policy.

But that doesn't mean there won't be barbs.

Walz was given credit for coining the label "weird" to describe his Republican opponents and the attack has stuck to Vance, with numerous viral videos and memes targeting the senator's past comments and encounters with voters.

"They really couldn't be more diametrically opposed, kind of like Harris and Trump," Kall said.

"I think there's going to be a lot of fireworks, given their personalities."

This report by The Canadian Press was first published Oct. 1, 2024.