As Vice-President Kamala Harris and her newly announced running mate, Minnesota governor Tim Walz, set off on their first joint battleground-state tour across the country, they’ve been shadowed on the campaign trail by one-half of their rival ticket: Republican vice-presidential hopeful J.D. Vance, who has scheduled a dueling series of events in the same areas.
Hours before Harris and Walz appeared at their first rally together Tuesday evening in North Philadelphia...