Critic on the left see Biden and Democratic leaders as blowing the crisis, as Republicans prepare for trillions of dollars in deficit spending and polls show support for the president’s response ticking up. Sanders has proposed several avenues of fast executive action, including one — applying the Defense Production Act to speed up the availability of crucial supplies — that Biden agrees with. But Sanders has been far more visible.

“Personally I think Bernie should turn the whole campaign into a coronavirus response operation,” wrote Nathan J. Robinson, the editor of the left-wing magazine Current Affairs. “It’s crucial to keep the primary going, because we have to choose a nominee who can handle the ongoing crisis effectively. If we don’t, a lot of people will die needlessly.”

The other knock on Biden has less to do with substance and more with mockery. Prominent Sanders supporters have criticized what they see as his lack of presence on the coronavirus response, promoting hashtags such as #WhereIsJoe, which trended for two days on Twitter; memes of milk cartons or movie posters with the “missing” candidate; and theories of how his 300 delegate lead could be reversed if Sanders outworked him.

“It’s a grave mistake,” Shaun King, a civil rights activist and Sanders surrogate, said of Biden’s minimal presence. “During a national emergency he just went missing.”