Shutting down businesses and schools felt to many people like a natural response to the COVID-19 pandemic. But the extended coronavirus lockdown of 2020 did not follow any widely-accepted standard strategy; lockdowns were sporadic and short-lived during the 1918 Spanish flu pandemic, the most recent historical parallel. Encouraging and coercing tens of millions of people to shelter in place in 2020 was one of the most radical social engineering experiments in modern history, as novel as the coronavirus itself.             The political impulse to cancel events and close nonessential services we experienced during the spring and summer of 2020 is reemerging as the highly contagious, albeit anecdotally less severe, omicron variant sweeps through New York City and other hotspots. Broadway theaters, rock and hip-hop performers have canceled performances, the Rockettes closed their season a week early and Mayor Bill de Blasio is considering curtailing attendance at the city’s annual ball drop at Times Square. Rumors that New York City…