In New York, emergency rooms are overcrowded and refrigerated trucks house dead bodies in the street. In California, thousands of hospital beds are sitting empty and the state recently lent 500 ventilators to harder-hit states.

Despite having the nation’s largest population, frequent travel with China and the first confirmed case of community spread in the country, California has only 15,865 cases of Covid-19 and 374 deaths as of Tuesday, compared with 138,863 cases and 5,489 deaths in New York state, according to their public...