Donald Trump was unlucky that a once-in-a-century pandemic struck in his re-election year. And Joe Biden is lucky that the current monkeypox outbreak is relatively mild. But his administration’s bumbling response belies Mr. Biden’s 2020 argument that he would have handled Covid better.

Monkeypox, first identified in lab animals in 1958, is a close relative of smallpox, though it is less lethal and contagious. Periodic outbreaks have occurred in Central and West Africa, where the virus is endemic and spreads among wild animals. Humans can catch it through direct contact with the skin lesions of an infected animal or person.