The novel coronavirus is already hitting the leadership of other countries. Iran’s gerontocracy and its Parliament have been heavily hit, the The United Kingdom's health minister has tested positive, and Canada’s leader, Justin Trudeau, is self-quarantining after his wife tested positive.

Yet the reality ahead for Congress—and the U.S. population writ large—is almost certainly much worse than a handful of cases. Germany’s chancellor, Angela Merkel, was blunt that nearly two-thirds of its population will likely face the virus in the coming months, and Congress’ own attending physician, Dr. Brian Monahan, said in a staff briefing Tuesday that a third or more of the U.S., from 70 million to 150 million people, will be affected by the virus in the coming months.

If even just half of Congress’ 535 voting members get COVID-19 in the months ahead—and if the virus' infection profile follows the rough outline medical experts are seeing globally, in which 80 percent of cases are relatively mild and just 20 percent are serious, Congress might see more than 50 serious cases requiring hospitalization. (Of course, given Congress’ advanced average age, its risk might actually be worse than the overall population's.)

So what happens when dozens of lawmakers are suddenly lying in quarantine, confined to hospitals beds across the country, from their districts to the capital, unable to make it to the floor to vote?

Since the beginning of the Cold War, Congress has been woefully disengaged in thinking about its own mortality and planning for its own survival. President Dwight D. Eisenhower effectively had to build the secret Cold War congressional bunker at West Virginia’s Greenbrier Hotel of his own accord after Congress dragged its feet on planning how it would survive nuclear war. In the first two decades of the Cold War, more than 30 bills were introduced to deal with how to continue functioning in the event of a widescale death of its membership, yet while three such bills passed out of the Senate, all of them died in the House. Eventually, Congress gave up the question entirely.

There are two catastrophic scenarios for Congress: The death of a large number of members and the incapacitation of a large number of members. Each comes with massively different outcomes in terms of its impact on legislative business and massively different outcomes for democracy.

The outright death of members of Congress puts in motion a relatively straightforward process, albeit a potentially slow one. The Senate, with its tradition of appointment by state legislature, largely has procedures to allow itself to reconstitute quickly through gubernatorial appointments, followed by special elections. The House, which prides itself on direct election by the people, has long fought any effort to allow for emergency appointments to the body, so any vacancies would be filled only by special elections, a process that would take months.

As representatives and senators die and vacancies arise, Congress can keep legally functioning no matter how small its remaining elected membership becomes—even though a notably smaller Congress might find its public legitimacy in question. Norm Ornstein—the scholar who has most consistently raised alarms about congressional continuity—pointed out after 9/11 that Congress has, since the Civil War, interpreted the quorum necessary for it to function as consisting of the majority of members “duly chosen, sworn, and living,” a definition settled on as a workaround to avoid the unpleasantness of the many senators and representatives who departed as the Confederacy seceded.

Nuclear war and terrorist attack scenarios contemplated, for instance, that even the death of 300 representatives, bringing the size of the House to 135, would allow a quorum of just 68 congressmen and congresswomen to continue legislating, leaving aside any uncomfortable questions about the partisan skew of those who survived and who would thus be making sweeping decisions about emergency measures.