Harris Grapples With How to Use Biden on the Campaign Trail

As she abruptly went from No. 2 on the Democratic ticket to No. 1, Vice President Kamala Harris had a decision to make: How should she deploy President Biden on the campaign trail?

Given that Democrats had pushed Mr. Biden out because of concerns about his age, mental fitness and ability to defeat former President Donald J. Trump, would she be best off distancing herself from the 81-year-old president she had served for nearly four years and focus instead on establishing her own political identity? Or should she continue to embrace Mr. Biden and the more popular of his policies?

And on the most practical level: Where should Mr. Biden go to campaign for her? How often? And what should he say?

Her answers are now starting to emerge. Ms. Harris and the people running her campaign plan to use the president — but carefully, and in a targeted way. The president and vice president will campaign together some, but not too much. And Mr. Biden will travel mostly to the important swing states of Pennsylvania, Wisconsin and Michigan, where he still appeals to white, working-class voters and union members.

“He gets an enormous amount of credibility in those blue wall states because he’s ‘Workin’ Joe Biden,’” said Cedric Richmond, a former administration official who is now advising Ms. Harris’s campaign. “People are underestimating the Democratic Party’s love for Joe Biden. It just highlights how many different messages he can give and the different places he can go.”