The schedule is especially packed in New Hampshire, an early presidential nominating state where there is a competitive Senate race Democrats are flocking to this month.
Gov. Gavin Newsom of California taking the stage during a campaign event for Representative Chris Pappas, the Democratic Senate nominee, in Exeter, N.H., on Saturday.
The string of sharp queries, some from voters who said they had supported him and President Donald Trump, previewed the rocky path Vance may face trying to answer for the administration's record if he runs for president himself in 2028.
The battle for the Senate in the midterm elections will determine how much room Donald Trump has to maneuver during the second half of his term: no legislation reaches the White House without first passing through the upper chamber.