In Scranton, Pa., it’s as though President Biden never left.

In the final weeks of the presidential campaign, Mr. Biden has been cast in the shadow of Vice President Kamala Harris amid concerns that his unpopularity could be a liability in her race against former President Donald J. Trump. But as he rallied union members in his hometown on Saturday during one of his last campaign events in office, Mr. Biden was in one of the few places Democrats feel he can still help Ms. Harris on the campaign trail.

“When he comes into this town, he is the top of the ticket,” said Sam Kuchwara, a 70-year-old retiree and veteran who is a native of Scranton. “He’s definitely more popular here than Harris.”

Scranton is certainly the exception in that respect. Mr. Biden rattled Democrats this week when he appeared to call supporters of Mr. Trump “garbage” while denouncing racist comments made by a comedian at a Trump rally. Even though Mr. Biden later explained that he had meant that the comedian’s “hateful rhetoric” was garbage, Ms. Harris had to spend time on the campaign trail distancing herself from the comment.

Ms. Harris’s rallies are far more enthusiastic and energetic than Mr. Biden’s, with crowds of thousands dwarfing those at his events. But Harris campaign officials believe that the incumbent president can still provide a key benefit to Ms. Harris by rallying working-class white voters and union members in battleground states.