The US has a Covid-19 test shortage. Who should get them?

The debate over how to allocate limited coronavirus tests, explained.

Testing is an essential part of resolving the Covid-19 coronavirus pandemic.

It’s essential to determining who has the virus, which can spread from people who may not exhibit any symptoms at all, sometimes for weeks. These unwitting spreaders are prolonging the pandemic, forcing the government to enact costly economic shutdowns. The way to relax these measures is to test people, sometimes repeatedly, and isolate the infected.

But since there still aren’t enough tests in the US to go around, who...