“They’re doing it because people who are in political leadership always think that if you do something dramatic and visible that you’ll gain popular support,” Lawrence O. Gostin, a professor of global health law at Georgetown University, told The Washington Post. “They couldn’t have any sound public health advice.”

We should keep this sense of caution in mind in case American politicians begin pushing for travel bans, overbroad quarantines or other measures that might not be supported by the science.

You might wonder what the great harm is — if the government needs to temporarily limit people’s movements or prevent some people from entering the country, shouldn’t it take those measures in the face of dangerous illness? Perhaps, but given the checkered history of quarantines — throughout history, they have been used to persecute the marginalized — lawmakers and the media should rigorously examine the bases for any such restrictions. We should especially make sure any restrictions imposed are indeed temporary and adhere to the science — something we don’t always do. Consider that 30 years after the AIDS outbreak, men who have sex with men are still restricted from donating blood in the United States, long after the scientific basis for such a ban has passed.

So far, President Trump has offered a measured response to the virus. “We have it totally under control,” he said this week. But online, misinformation about the scale of the virus is already trending. (It is not, as you might have read on Twitter, “thermonuclear pandemic level bad.”) So are racist memes blaming Chinese people and Chinese culture for the virus.

I fear that the conditions are ripe for a situation similar to what occurred in the summer of 2014, when an outbreak of Ebola overran West Africa. After the Obama administration scrambled to bring home two American health workers who had become infected with the disease in Liberia, Trump went on a monthslong Twitter tirade about Ebola.

The future president favored extreme isolationism, seeing no benefit to American help in Africa. “People that go to far away places to help out are great-but must suffer the consequences!” he wrote — ultimately sparking a growing partisan movement against the government’s response to the virus.

Today, Trump runs an administration that is hemorrhaging scientific expertise, and his political agenda is rife with efforts to target immigrants, minorities and the poor. In 2016, a terrorist attack prompted Trump to propose banning Muslims from the country; when he won the White House, he instituted a version of that ban.