Harris campaigns in Arizona, while Trump is in Montana

U.S. Vice President and Democratic presidential candidate Kamala Harris and Democratic vice presidential candidate, Minnesota Governor Tim Walz react during a visit at a campaign office Friday, in Phoenix, Ariz. (REUTERS/Elizabeth Frantz)

U.S. Vice President Kamala Harris campaigned in Arizona on Friday, hoping her less-than-one-month-old bid for the White House can put Republican candidate Donald Trump on the back foot in the West.