In light of the threat that the new coronavirus presents to people in the U.S., are stay-at-home orders and mandatory business closures constitutional? Proponents of the view that these orders are unquestionably constitutional point to court cases broadly authorizing governmental actions to contain disease. And state governments do have broad authority under their police powers to respond to pandemic threats. Judges deferentially review legislative and executive actions in response to pandemics threats. Nonetheless, even the most broadly worded decisions do not provide state governments with a carte blanche, as these very same cases also note.

As Felix Frankfurter put it, “Constitutionality is not a fixed quality; in crucial cases it resolves itself into a judgment upon facts.” This is reflected in the constitutional requirement that exercise of the police power, even in the face of a pandemic, must nonetheless be “reasonable.” To be sure, reasonability is interpreted by courts in a manner highly deferential to legislative and executive actions. Arguments over public policy are made more appropriately to legislators and executives than to courts. Nonetheless, even under deferential rationality review, courts can provide a “sober second look” at the possibility of policy overreach by government officials in the grip of pandemic panic. That is one of the purposes, after all, for buffering judges from the full force of political pressure faced by legislators and executives.

But what counts to determine constitutional “reasonability” for legislatively-authorized executive actions that respond to a pandemic? Judicial tests generally, if often implicitly, weigh the costs and benefits of a given policy. And government actions get the benefit of the doubt unless they trench on suspect categories like race or on special domains such as interstate commerce.

What goes into these calculations? The threat that the disease itself poses obviously counts. We can measure this in terms of the probability of catching the disease, and the magnitude of the possible effects, whether death or injury.

But two aspects of the cost of the government’s action also count in determining constitutional reasonability: the “fit” between how a policy classifies people and the harm it seeks to reduce, and, secondly, the cost the government’s action imposes on people burdened through the classification.

Before getting to the cost, we need to unpack this notion of the “fit” between a governmental action or classification and the harm the government actions seek to address.

By “fit,” I mean the degree to which a government’s policy is overinclusive or underinclusive.

“Overinclusive” means that a policy burdens a set of people larger than the set of people who constitute the threat. A classic example of an overinclusive governmental action is a roadblock set up at 2 a.m. The regulated trait is “driving at 2 a.m.” The harm sought to be prevented is “drunk driving.” Yet even at 2 a.m., the set of people with the trait—driving at 2 a.m.—is larger than the set of people who do the harm.

“Underinclusive” means that a policy action (and associated cost) is imposed on a set of people smaller than the set of people who constitute the threat. A curfew that applies only to people less than 21 years old, for example, is underinclusive. After all, people over the age of 21 engage in mischief as well as people under the age of 21. Yet the curfew burdens only those under 21. (Policies can be both over- and underinclusive. For example, raising the drinking age to 21 in order to reduce drunk driving is both overinclusive and underinclusive: Many 18 to 21 year-olds drink responsibly, so the law’s prohibition is overinclusive relative to the harm it seeks to address, and many people over the age of 21 drink irresponsibly, so the prohibition is also underinclusive relative to the harm it seeks to address.)

Almost all laws are over- or underinclusive to some degree. Constitutionality does not require a perfect fit. But the reason or benefit for a law’s overinclusivity relative to the cost or burden of an overinclusive requirement all go into determining its constitutional “reasonability.”

The reason for overinclusive governments actions is that more carefully-tailored policies may not address the harm in as effective a manner relative to keying on less overinclusive traits. Consider again our drunk driving example: Pulling over only drivers whom the police observe to be driving erratically is far less overinclusive than a roadblock. But it would also miss many drunk drivers whom a roadblock would catch.

The tradeoff between the two means of apprehending drunk drivers at 2 a.m. is this: The roadblock is more effective at catching drunk drivers than is police observation alone. Its over-inclusiveness is its virtue. Nonetheless, there is a cost imposed on those who have the trait but who do not do the harm—late-night drivers who haven’t touched liquor that night. This is normally a low cost. The delay of a few minutes.

So, too, stay-at-home orders and business closure orders are also overinclusive for a reason. We don’t know who has the virus. Yet the regulated trait is very broad indeed. The regulated trait is “being a person” for stay-at-home orders, and being a “non-essential business” for closure orders. The benefit of both requirements is to slow or stop the spread of the virus. (These orders are also underinclusive given their many exceptions. But that for a separate discussion.)

The problem with the stay-at-home orders and business-closure orders is not their bare over-inclusiveness. The problem is the much higher burdens these orders impose on people relative to the costs imposed in the cases invoked today to suggest the ostensible constitutionality of these orders.

Perhaps the most cited case ostensibly settling the unquestioned constitutionality of today’s stay-at-home and business closure orders is the 1905 Supreme Court case, Jacobsen v. Massachusetts. This decision approved mandatory vaccinations for small pox in Massachusetts.

It is true that the Supreme Court approved the significantly overinclusive governmental requirement in that case. And the Court does use very broad language.

Often ignored in today’s invocations of the decision, however, are two aspects of the case. The first is that the Court carefully cabins its legal conclusion in a discussion of the relatively low costs of the state’s overinclusive requirement. Also ignored today is that smallpox represented a much greater threat to life and health than the coronavirus does.

Starting with the last point first. At the time of the Jacobson decision, the most prevalent form of smallpox had a fatality rate of 30 percent. This is much higher than even maximum estimates of today’s coronavirus threat except perhaps for the very highest risk groups.

But it’s the disparity in the costs imposed by the overinclusive vaccination requirement relative to the costs of the current stay-at-home and business-closure orders that is most ignored. The Supreme Court itself observed in Jacobsen that courts may need to intervene should the government’s response be “unreasonable” or “might go so far beyond what is reasonably required for the safety of the public.” Justice Harlan, writing for the Court:

Smallpox being prevalent and increasing at Cambridge, the court would usurp the functions of another branch of government if it adjudged, as matter of law, that the mode adopted under the sanction of the State, to protect the people at large was arbitrary and not justified by the necessities of the case. We say necessities of the case because it might be that an acknowledged power of a local community to protect itself against an epidemic threatening the safety of all, might be exercised in particular circumstances and in reference to particular persons in such an arbitrary, unreasonable manner, or might go so far beyond what was reasonably required for the safety of the public, as to authorize or compel the courts to interfere for the protection of such persons (emphasis added).

In this regard, the cost of Massachusetts’ overinclusive vaccination requirement was very low indeed. It was, literally, a skin prick. And what of the risk to health of the vaccination itself? Here the proper comparison is the probabilistic threat to the community (including the possibility that the non-inoculated person would be at risk from smallpox) relative to the ex ante threat of the vaccination to the health of an individual. The Court took judicial notice that while medical professionals:

have recognized the possibility of injury to an individual from carelessness in the performance of it, or even, in a conceivable case, without carelessness, they generally have considered the risk of such an injury too small to be seriously weighed as against the benefits coming from the discreet and proper use of the preventive . . .

Weighing the marginal expected benefit of the vaccine against the marginal expected cost, the Court deferred to the judgment that the benefits easily exceeded the costs. That is, in the justices’ view, the requirement was constitutionally reasonable.

Significantly, however, the Court expressly limited its holding to persons for whom the cost of the overinclusive requirement was very low:

we are not inclined to hold that the statute establishes the absolute rule that an adult must be vaccinated if it be apparent or can be shown with reasonable certainty that he is not at the time a fit subject of vaccination or that vaccination, by reason of his then condition, would seriously impair his health or probably cause his death. No such case is here presented.

Today’s stay-at-home and business closure orders impose much, much heavier burdens on the overinclusive class of individuals than did the overinclusive requirement in Jacobson. The cost of today’s orders is much greater than a skin prick. While not rising to the equivalent of death, nonetheless, the very substantial disruptions resulting from forced unemployment and business closures—poverty, stress, limited future life prospects—could easily be ranked by many as the equivalent of a serious impairment of health. And these costs are incurred with certainty by many swept into the overinclusive requirements.

So, too, there are less burdensome alternatives that can dramatically reduce the threat of unchecked coronavirus at a small fraction of the cost imposed by stay-at-home and business-closure orders: Masking, distancing, cleaning. (We might here note the irony that widespread resistance to masking requirements invites government officials to take the far more burdensome steps of imposing stay-at-home and business-closure requirements.)

The Court rejected the extreme libertarianism asserted against Massachusetts’ overinclusive vaccination law in its 1905 decision. Contrary to today’s narrative, however, the application of the Massachusetts’ decision to today’s coronavirus stay-at-home and business closure requirements is far from straightforward. With a much lower expected benefit and much higher costs resulting from today’s overinclusive government requirements relative to those litigated in Massachusetts case, the constitutional reasonability of today’s requirements are much more constitutionally dubious, even when applying the courts’ most deferential standards of review.