• The spread. From the time the first case emerged in Wuhan on Nov. 17 to the moment when China/the World Health Organization acknowledged human-to-human transmission on Jan. 20, Wuhan exported between eight and 16 undetected cases to the U.S. through air travel, giving rise to 1,000 to 9,000 cases in the U.S. by March 1, according to a U.S.-Chinese modeling project. Another modeling group estimates that other Chinese cities exported 2.9 cases for each case exported from Wuhan. As first reported by USA Today, many of the virus strains circulating in New York appear to have arrived by way of Europe.

Bottom line: It doesn’t get Donald Trump and other politicians off the hook for goofy statements and slow responses, but a global pandemic was likely unstoppable by Jan. 20.

• Testing. The CDC develops tests for its own internal use. The Food and Drug Administration requires that tests offered to the public be proved safe and effective. Government might have said “have at it, boys” and allowed anyone to make and sell anything and call it a Covid-19 test. This wouldn’t have been government.

Though the Trump administration is guilty of testing stumbles, unrealistic is the notion that enough testing could have been mobilized to contain a novel flu-like virus once it was widely established.

• The lockdowns. Imagine a problem that can be solved by holding your head underwater but stops being solved when you lift your head out. This is no solution. How can any society lift its stay-at-home order if there’s no vaccine and most people remain uninfected? Not even the Chinese, as we are about to learn, really have an answer. Yet it’s amazing how much congratulatory press coverage of the lockdowns doesn’t acknowledge this obvious Catch-22. By now even the most tunnel-visioned epidemiologist must admit the lockdown cure will soon be worse than the disease, imposing social destruction beyond imagining.