Donald Trump’s first instinct when it came to the coronavirus was to dismiss the threat as overblown, over there, and “totally under control.” His second was to use the pandemic as an opportunity to show off his world-historical leadership skills by treating the virus as a threat on par with World War II.

Both reactions were driven by politics, not evidence. The first was unquestionably wrong. The second needs to be questioned aggressively before we impose solutions possibly more destructive than the virus itself.

On Thursday, Gov. Gavin Newsom of California commanded the people of his state to stay home. That’s roughly 40 million people. He anticipates that about 25 million Californians will be infected by the virus over the next eight weeks.

Where does that projection come from? The governor cites a “model” used by state planners, the accuracy of which can only be guessed. How long will it be enforced, and for how long can it be sustained? Nobody knows. The only certainty is that, in the midst of a crisis, politicians are rarely penalized for predicting the worst possible outcome. If it comes to pass, they seem prophetic. If it doesn’t, they take credit for averting catastrophe.