It is early yet — which even Mr. Biden’s friends allow as they hold their breath — and precedent offers good reason to question whether his streak of mostly error-free days can last.

But his staff has sought to mitigate the risk by effectively recreating the trappings of the vice presidency: guarding question-and-answer sessions, selecting safe interview settings and remaining all but glued to his hip when he greets voters on rope lines, dips into ice cream shops and steps out of the black Chevy Suburbans that are indistinguishable from the Secret Service models he once rode in.

There are notes on his lectern to remind him of key policy points, depending on the locale, and his schedule has been carefully planned: He has appeared at nearly as many fund-raisers (five) as he has rallies (six).