From the moment former vice president Joe Biden became the Democratic Party’s presumptive nominee for president, one qualification has loomed as most important for his running mate: that she or he be prepared to serve as president. Sen. Kamala Harris, the California Democrat whom Biden announced Tuesday as his selection, meets that test.
Of course, in theory that should always be the primary consideration for a vice president. Too often, though, candidates have been more influenced by electoral college arithmetic. There’s good reason to think that Harris, a gifted politician, can help lift the ticket, but California is not a state where Biden needs help. At 78, though, he would be far and away the oldest person to be sworn in as president, and demographic reality dictated a choice of someone who could plausibly step in.