On Tuesday (Aug. 6), Vice President Kamala Harris and her newly elected running mate, Minnesota Gov. Tim Walz, made their first public appearance and speech together at a campaign event in Philadelphia.

Next, Harris and Walz will campaign in Pennsylvania, then Wisconsin, Michigan, Arizona and Nevada.

Harris chose Walz as his deputy with the goal of expanding Democratic support in the Midwest and other key swing states. Walz's Midwestern background and pro-life image could help attract more middle-of-the-road voters, which is especially important in the current tight race.

Additionally, Walz has attracted left-wing support for his advocacy of marijuana legalization, worker protections, abortion rights and stricter gun control.

Previously, Walz pushed for one of the nation's most generous child tax credits in Minnesota, making it one of his key political accomplishments. His addition is expected to spread the policy across the country and help more low-income families.

In his first speech in Philadelphia, Walz sharply criticized former President Trump and Ohio Senator Vance, receiving applause and laughter from the audience. He emphasized the rise in crime during Trump's administration and mocked Vance's background.

After Harris announced his choice of Walz as his running mate, Trump's campaign labeled Walz a "dangerous liberal extremist" who it said was trying to impose California values on the nation.

The latest University of Massachusetts Amherst poll shows Harris leading Trump by three points nationally, compared to Trump's four-point lead over Biden in January. In swing states, Harris and Trump are neck-and-neck in favorability.