When the federal and state governments have overlapping, competing powers, such as over economics or crime, they further must rely on their own resources for enforcement — which makes any White House command virtually impossible to carry out. In another set of federalism cases, these decided by the Rehnquist Court, a conservative majority forbade Congress from “commandeering” state officials into enforcing federal commands. If the federal government were to decide to re-open all businesses, it could call upon only on its own law enforcement officials to execute the policy. Washington simply does not have enough resources to manage such a vast task; the FBI, the closest we have to a national police force, has fewer agents than the NYPD has sworn officers.

Our unique federal system does not mean that Trump remains utterly powerless to bring the nation out of this unprecedented economic contraction. But he will have to rely less on command and more on persuasion. Congress more often gets its way in areas outside its direct control, such as in education, health care, and welfare, by paying states to adopt a uniform national policy. Article I of the Constitution provides that Congress has the power to tax and spend to “provide for the common Defence and general Welfare of the United States.” The spending power already has provided the Trump administration with its most effective weapons in fighting the pandemic: It can provide critical supplies and medical equipment, transfer funds to states and cities or hospitals, and fund research on a vaccine and cure.

Trump could use the money appropriated by Congress to respond to the pandemic as a reward for states that end their lockdowns in May. He could send disaster relief funds, made available by the Stafford Act in time of emergency, or allocate more medical equipment and protection supplies to these states, perhaps on the ground that they risk greater harm from the virus in exchange for opening up.