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For observers in the United States, it was shocking enough when, in January, the Chinese government effectively sealed off Wuhan, larger in population than New York City. Officials shut down public transportation and blocked highways, confining residents and visitors alike in an attempt to stop the spread of the new coronavirus.

But in the weeks since, the measures have become more drastic still. The quarantine-style lockdown has since been extended to include more than 50 million people elsewhere in China. Officials have ordered door-to-door checks in Wuhan to round up the infected for further isolation. Anyone who hides infections, one official said, “will be forever nailed to history’s pillar of shame.”

Putting aside the question of whether such radical measures are even effective, China’s government generally has much more authoritarian control over its population than the American government has over its. If a fast-spreading, deadly epidemic should threaten the United States, could the U.S. government do the same? The answer is yes: American government officials do have extensive authority to implement public-health measures to stop an epidemic, as the Americans on the Diamond Cruise ship in Yokohama, Japan, are now learning. According to The Washington Post, they were told on Saturday that following their two-week quarantine aboard the ship they would face an additional two-week quarantine back in the United States.

In the U.S., quarantine is the most extreme use of government power over people who have committed no crime. As a legal matter, the U.S. Supreme Court recognized a seemingly unlimited local power to quarantine as early as 1824, in the case Gibbons v. Ogden. It reaffirmed this power in 1900, noting that “from an early day the power of the States to enact and enforce quarantine laws for the safety and the protection of the health of their inhabitants … is beyond question.”

Government officials can prevent travel, require vaccinations, make people submit to medical exams, and commandeer private property. Even those who are not sick can be ordered into quarantine—confined to their home or another location with others who may also have been exposed to a virus. When quarantine is medically justified, individual rights give way to the greater good. As the Court stated in Jacobson v. Massachusetts in 1905, “Upon the principle of self-defense, of paramount necessity, a community has the right to protect itself against an epidemic of disease which threatens the safety of its members.” The constitutional structure tolerates such substantial restriction of liberties for at least a limited time in a true public-health emergency. That said, constitutional protections during quarantine do exist. For example, health officials must use the least restrictive means consistent with medical guidance, and the government must have good reason to believe you’ve been exposed.

But the average American may be surprised to learn who holds the authority to order such public-health measures. Except at the nation’s borders, the federal government, with the expertise of the Centers for Disease Control and Prevention, is not in charge. America’s defense against epidemics is divided among 2,684 state, local, and tribal public-health departments. Each one is responsible for monitoring people within its jurisdiction, imposing isolation or quarantine as needed. CDC officials are “preparing as if [the new coronavirus] is the next pandemic,” but in reality, the laboring oar falls to state and local health departments.

The federal government’s quarantine powers at U.S. borders are indeed extensive. The Department of Homeland Security has implemented a travel ban on noncitizens who have been anywhere in China recently. U.S. citizens, by contrast, cannot be turned away at the border, but they can be ordered into quarantine to be monitored, at present for up to two weeks. The secretary of health and human services announced quarantine measures for returning citizens not long after the CDC issued its first federal quarantine order in more than 50 years—for the first planeload of people evacuated from Wuhan by the U.S. State Department.

Federal quarantine orders, however, are implemented and enforced by state health authorities, not federal officials. That means state and local health departments provide the labor, set the rules, monitor people who might have been exposed to the virus, and trace the contacts of those who fall ill. The federal quarantine order for the 195 evacuees from Wuhan? That order was able to prevent them from leaving the plane they arrived in. The federal government could also order the quarantine of an entire cruise ship at one of the nation’s seaports—as Japan has done. But otherwise, federal quarantine orders have a pretty limited effect. When one of the Wuhan evacuees wanted to leave the military base in California where the group was under quarantine, a state-level quarantine order was necessary to prevent that from happening. This is because the quarantined group was no longer at a point of entry, or in an airplane, and was thus subject to the jurisdiction of the local health department where they were quarantined.

Despite extensive federal measures to protect the U.S. from threats originating abroad, inevitably a virus will get through screening (as indeed the Wuhan coronavirus already has). This is where the weakness of a federalist system of national health defense is exposed. States may choose to ignore federal quarantine guidelines, or they may decide that more drastic measures are required, such as a lockdown against a neighboring city or region. Extreme measures may be necessary in a public-health emergency, but the variation from one location to another could also make an epidemic worse as each state makes its own rules, looks out for its own interests, and relies on its own resources. Jurisdictional boundaries are enforced, among other reasons, to preserve limited budgets.

This unique brand of public-health federalism can make implementing a national strategy in the event of a threatened epidemic very difficult. During the 2014 Ebola scare in the U.S., fierce public debate ensued about what measures to take. Panic set in as political leaders squabbled and it became clear that there was no single, national plan to follow. State and local health officials are the final authority on what preventive measures to take within their jurisdiction. With this setup, having an effective national strategy when one is needed is complicated if not impossible.

Does the U.S. Constitution in fact prevent a larger role for the CDC in setting quarantine policy within the country? At least when this question was previously asked, more than a century ago, Congress thought the answer was no.

The question emerged in the late 19th century, when yellow-fever epidemics in the southern U.S. sent panicked citizens fleeing, and cities and towns throughout the region closed their borders to one another. The nascent U.S. Public Health Service set up camps in Alabama and Florida for refugees, as they termed them, who had nowhere to go but did not wish to return to a place in the midst of an epidemic. After long debate, Congress responded with the 1890 Epidemic Diseases Act, providing federal authority over state and local quarantine, though many senators at the time did vote against it, believing it to be unconstitutional. As a result (on paper at least), the federal government may impose (or lift) quarantines in the interior whenever specified contagious diseases threaten to spread “from one state … into any other state.” The CDC’s modern-day interstate authority is limited primarily to “do not board” orders to prevent air travel within the U.S. by persons known to be ill, and relies on state health departments to request the order.

But the question has not been tested, or even debated, in modern times. Until we have a need to test the limits of the federal government’s interstate quarantine authority (and let’s hope we don’t), who is in charge of setting national policy in the event of an epidemic emergency? The surgeon general of the United States? The CDC? And will that authority be believed?

It needs to be, because with public health under local political control, one state or local government’s failure could mean the more rapid spread of a virus anywhere in the nation. State and local jurisdictions have limited medical and scientific resources to understand the transmission of complex diseases and to form independent judgments about the best means to control spread. Quarantine policies or other emergency measures set by the federal government are not better just because they can provide uniform rules throughout the nation—federal officials, too, can overreact in counterproductive and rights-threatening ways. But clear lines of authority may be needed.

This is where the world-leading scientific expertise of the CDC is essential. With a SARS-like virus or pandemic flu with the ability to spread through the air, the potential exists for constitutional conflict that could be too fast-moving for courts to intervene, either in favor of measures that state or local governments wish to take or to elucidate the boundaries of interstate quarantine authority such that a federal quarantine order would take precedence over contrary state or local measures. If it comes to that, the CDC’s credibility will be necessary to coordinate the responses of all the different jurisdictions, or something much worse than a constitutional dispute could befall the country.

This story is part of the project “The Battle for the Constitution,” in partnership with the National Constitution Center.

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