As the number of COVID-19 cases skyrockets nationwide, the extent of the public health response varies from one state — and sometimes one town — to the next. … Nowhere are these regulatory disparities more counterproductive and jarring than in the border areas between restrictive and permissive states; for example, between Washington and Idaho, Minnesota and South Dakota, and Illinois and Iowa. In each pairing, one state has imposed tough and sometimes unpopular restrictions on behavior, only to be confounded by a neighbor’s leniency.