This week, as cities and states began locking down, stock markets tumbled and jobless claims hit record levels, Mr. Trump again played down the impact of the pandemic and said, with no evidence and contrary to available research, that a recession would be deadlier than the coronavirus.

Overstating potential treatments and policies

The president has also dispensed a steady stream of optimism when discussing countermeasures against the virus.

From later February to early March, Mr. Trump repeatedly promised that a vaccine would be available “relatively soon” despite being told by public health officials and pharmaceutical executives that the process would take 12 to 18 months. Later, he promoted treatments that were still unproven against the virus, and suggested that they were “approved” and available though they were not.

Outside of medical interventions, Mr. Trump has exaggerated his own policies and the contributions of the private sector in fighting the outbreak. For example, he imprecisely described a website developed by a company affiliated with Google, wrongly said that insurers were covering the cost of treatment for Covid-19 when they only agreed to waive co-payments for testing, and prematurely declared that automakers were making ventilators “right now.”

Often, he has touted his complete “shut down” or “closing” of the United States to visitors from affected countries (in some cases leading to confusion and chaos). But the restrictions he has imposed on travel from China, Iran and 26 countries in Europe do not amount to a ban or closure of the borders. Those restrictions do not apply to American citizens, permanent residents, their immediate families, or flight crews.

Not only were these restrictions total and absolute in Mr. Trump’s telling, they were also imposed on China “against the advice of a lot of professionals, and we turned out to be right.” His health and human services secretary, however, has previously said that the restrictions were imposed on the recommendations of career health officials. The Times has also reported that Mr. Trump was skeptical before deciding to back the restrictions at the urging of some aides.

Blaming others

The Centers for Disease Control and Prevention sent test kits to states in February, some of which were flawed and produced inconclusive readings. Problems continued to grow as scientists and state officials warned about restrictions on who could be tested and the availability of tests overall. Facing criticism over testing and medical supplies, Mr. Trump instead shifted responsibility to a variety of others.