Nonetheless, Trump is trying to convince voters that the swine flu was at least a dry run, and Biden stumbled. “The most notable thing he did was to erroneously tell the country not to fly on airplanes, and the Obama administration had to run around to clean up the mess,” Tim Murtaugh, a Trump-campaign spokesperson, told me.

Trump has had less to say about Biden’s response to the far more dangerous epidemic the Obama administration confronted, the Ebola outbreak in West Africa in 2014. Biden’s former chief of staff, Ron Klain, who advises his campaign, led the administration’s efforts to contain the outbreak as the White House’s Ebola czar. Here, too, Biden wasn’t a central player, though he helped arrange medical assistance to West Africa and gave advice on how best to contain the outbreak. Despite widespread public fears about Ebola, the response was successful: Only 11 people were treated for the disease in the U.S. from 2014 to 2016, according to the CDC.

Perhaps the most enthusiastic argument Trump’s political advisers have made lately about Biden is that he is too close to China, a relationship they argue could compromise America’s national security and public health. Tying Biden to China fits within a larger strategy of demonizing that country and reviving the economic-nationalist argument that Trump successfully invoked in the 2016 race.