“Historically, the federal government has been fairly cautious in writing public health laws not to exceed its authority under the Constitution. The federal law and regulations dealing with quarantines, for example, does not claim the power to impose a quarantine on any American anywhere in the nation. Rather, they permit quarantines of individuals entering the country or crossing state borders, while leaving the question of whether to quarantine individuals within a state’s borders to the state itself.
Similarly, the raft of stay-at-home and business closure orders imposed on many Americans, as well as various orders closing public schools, have typically come from state or local officials. And, in many cases, these officials have already signaled that they plan to keep these orders in place well beyond Trump’s May 1 deadline.”