“There is no U.S. global leadership and no U.S. model,’’ Ms. Major added. “Success would be that you manage the pandemic at home, rally allies around you, lead the alliance, supply global public goods and organize the global response, as with Ebola.”

Instead, American institutions “don’t seem to be able to cope at home,” she said, and there is “a Trump response to act alone.’’

The United States did provide some early aid to China. But in general, the administration has left even close allies to fend for themselves. Mr. Trump has defended his ban on all travel from the European Union, but he did not bother to consult with European leaders or even give them advance notice.

[Update: Boris Johnson, U.K. Prime Minister, has the coronavirus.]

The United States has the leadership of the Group of 7 industrialized countries this year, but it was the energetic French president, Emmanuel Macron, who called Mr. Trump twice in 10 days to suggest a G-7 virus summit by videoconference. Mr. Trump agreed, but left Mr. Macron to organize it.

Germans and Europeans generally are angry about accusations from German officials that the Trump administration, and reportedly Mr. Trump himself, offered $1 billion to a German pharmaceutical company, Cure-Vac, to buy monopoly rights to a potential Covid-19 vaccine.

The White House denies the accusations and the company has denied receiving a takeover offer. But its lead investor made clear there was some kind of approach.