Democrats Harris and Walz test his Midwest credentials at rallies in battleground states

US Democratic presidential candidate Kamala Harris and her new running mate, Minnesota Governor Tim Walz, put his Midwestern credentials to the test on Aug 7 with rallies in the battleground states of Wisconsin and Michigan.

"Hello, Eau Claire!" Mr Walz said to a boisterous crowd of thousands in the Wisconsin city about 130km away from his home across the Minnesota border. "Isn't it good to have a candidate who can pronounce the name correctly?" The Democratic candidates are using their first joint campaign swing to introduce Mr Walz, a former teacher and football coach and a veteran of the Army National Guard, to voters around the country after he beat out better-known Democrats for the No. 2 spot.

They are also making their case against Republican rival Donald Trump and his running mate, US Senator J.D. Vance, with less than three months until the Nov 5 election.

"We are joyful warriors," Ms Harris said at an evening rally in Detroit, underscoring the sense of optimism that has enveloped Democrats since she replaced President Joe Biden at the top of the presidential ticket two weeks ago.

Polls show Ms Harris has erased the lead Trump had built during the final faltering weeks of Mr Biden's campaign, and a re-energised Democratic Party has flooded her campaign with donations.

The Harris campaign said it raised US$36 million (S$47.7 million) in 24 hours after announcing Mr Walz as the vice-presidential pick on Aug 6. The next day's rallies drew more than 27,000 people in total, according to the campaign.

Democrats regard Wisconsin and Michigan as near must-wins in the 2024 election. The states have loomed large for the party since Mrs Hillary Clinton's unexpected defeats there helped clinch Trump's 2016 win.