Read: The worst disease ever recorded

But on the other hand, there are some worrisome developments. Models suggest that the cases in China may number in the hundreds of thousands—many times what the government has reported. Perhaps a million or more people left Wuhan before the quarantines, and could be spreading the virus widely. Other countries are reporting cases of the virus among people who were not in China; there are even reports that individuals may be infectious before the onset of symptoms (a substantial complication to traditional public-health screening). And the economic impact of a massive epidemic in China on the global economy is difficult to predict.

What will Trump do about it? His track record offers us two data points, one horrible and one merely disappointing.

Trump briefly withdrew from politics after his “birther” campaign against President Barack Obama was discredited, but his next big public splash was a virulent, xenophobic, fearmongering outburst over the West African Ebola epidemic of 2014. Trump’s numerous tweets—calling Obama a “dope” and “incompetent” for his handling of the epidemic—were both wrongheaded and consequential: One study found that Trump’s tweets were the single largest factor in panicking the American people in the fall of 2014. How paranoid and cruel was Trump? He blasted Obama for evacuating an American missionary back to the United States when that doctor contracted Ebola while fighting the disease in Africa. Fortunately, Obama ignored Trump’s protests, and Kent Brantley was successfully treated in the U.S.; he continues doing good works today.

Obama’s strategy for combatting Ebola in West Africa—interventionist, aggressive, science-based—made a huge contribution to a global response that saved hundreds of thousands of lives, and protected the U.S. from an outbreak. Tom Friedman wrote that it was perhaps Obama’s “most significant foreign policy achievement, for which he got little credit precisely because it worked … [showing] that without America as quarterback, important things that save lives … often don’t happen.”

As president, Trump’s own handling of the second-worst Ebola outbreak in history—ongoing in Congo—has been more mixed. Regrettably, after four U.S. soldiers were killed in Niger in 2017, Trump imposed an isolationist edict that no U.S. personnel are allowed to be in harm’s way in fighting the disease. Top American experts who were in and near the disease “hot zone” in Congo have been withdrawn. Moreover, while the U.S. has sent aid, it has provided only a fraction of the assistance offered in past global-health emergencies, a step back from the leadership demonstrated by prior Democratic and Republican administrations. Within these constraints, however, Trump has allowed the experts at the U.S. Agency for International Development and the Centers for Disease Control to provide assistance; most surprisingly, Trump even allowed the medical evacuation of a possible Ebola case to the U.S. for treatment.