This is also our chance to remake crumbling urban infrastructure — to create more engaging outdoor public spaces and to radically improve public transportation.

Then there is climate change. Think of the coronavirus as a trailer for the horror flick of natural disasters to come. We have a chance to fortify urban space against future outbreaks of disease as well as the coming calamities caused by the changing weather — we can even do both at the same time. For instance, reducing automobile traffic in cities will not just cut emissions that warm the climate. It will also clean up the toxic air that hangs over our most populous areas, and is thought to increase the risks of respiratory diseases, including susceptibility to Covid-19. More walkable and bikeable urban design is good for the environment and our health; a study of commuters in Britain showed that biking to work was associated with lower risk of cardiovascular disease and cancer.

What’s important here aren’t the specific ideas, but the larger push for civic revitalization. The coronavirus does not have to kill cities — just our old idea of what cities were, how they worked, and who they were for.

Rethinking urban space in the aftermath of disease is hardly a new idea. If cities were going to be crushed by pestilence, they would have died millenniums ago. Disease has shaped the modern city, and the modern city has shaped disease.

The practice of epidemiology was born in the city, when John Snow, a London anesthesiologist, tracked the spread of cholera to a contaminated water pump in 1854. And much of the civic infrastructure we now take for granted — public parks, garbage trucks, sewers — was put in place partly to curb disease. Cities have overcome disease before, and they can do so again.

Yet at the moment, a grand project to rebuild American cities feels terribly elusive. Despite their economic and cultural importance, cities in the United States are often marginalized in politics and, more deeply, in our picture of how America should work. About 80 percent of Americans live in urban areas, but most say they’d rather live somewhere else.

Republicans use cities as a cudgel — supposedly crime-ridden “Democrat cities” became a mantra for President Trump. Democrats depend on big cities and their surrounding suburbs for the bulk of their voters, but when was the last time you heard a national Democratic politician make a forceful case for the beauty, creativity and importance of cities — for all that we owe to them, and all we may yet gain from them?