Scientists around the world have worked overtime to get a handle on Covid-19, yet one great unknown remains. We still don’t know for sure whether this is only a medical crisis, or also a medical system crisis.

The distinction matters for the novel coronavirus for the same reason it matters for other “natural disasters” that aren’t entirely natural. It is now widely understood that famines arise from local political failures in the trade and distribution of abundant global food supplies, not from local crop failures. Floods...