Thankfully, history has some insights for us here, and they turn out to have less to do with the Constitution than you might think. The first clue comes via the text of the C.D.C. order itself.

Instead of simply halting evictions and then laying out procedures and punishments under the new rules, the C.D.C. began the document with at least 27 paragraphs and 35 footnotes of preamble. There was a fair amount of throat-clearing about the threats of COVID-19 and some obviously relevant statistics in there, like a projection that “30–40 million people in America could be at risk of eviction.” But then came some odder stuff, like a sentence about how 35 million Americans move households each year under normal circumstances, and that “approximately 15 percent of moves are interstate.”

What exactly was the point?

I put the question to Mark A. Melton, a partner with the law firm Holland & Knight, who spent most of his free time in 2020 working pro bono for evicted tenants in his hometown of Dallas. We interviewed him and some of the tenants he’s helped for our ongoing video coverage of evictions.

“When you read the C.D.C. order, there’s a whole lot of language in there that seems very flowery, and statistics on how housing impacts viral transmission and issues like that,” Melton said. “The reason all that’s in there is because they all know it’s going to go to a court, and whatever judge looks at this — especially when it goes to the top — they’re going to look at all the reasons that they passed this.”

The C.D.C. needs to give specific types of reasoning for its pandemic interventions because of a law dating back more than 75 years: the Public Health Service Act of 1944, a law the C.D.C. cites in its order. The law empowered the United States Surgeon General to make and enforce rules “necessary to prevent the introduction, transmission or spread of communicable diseases” from foreign sources “or from one State or possession into any other State or possession.” Some of those powers to fight infectious disease have since been transferred to the C.D.C.

This law didn’t give the federal government new powers so much as consolidate a long and gradual shift of public health control from local authorities to federal ones, often driven by deadly epidemics. This 2002 Harvard Law School paper argues as much by laying out a fascinating history that begins in 1647, when the Massachusetts Bay Colony ordered ships from Barbados quarantined due to the threat of plague; through the 19th century, when a series of deadly yellow fever epidemics drove Congress to place some quarantine powers in federal hands; and up to World War II, when federal wartime powers expanded into all aspects of life.”

The 1944 law helped firm up a wartime effort to control the spread of malaria among civilians and service members. After the law’s passage, the Office of Malaria Control in War Areas — primarily responsible for spraying of insecticides — was directly succeeded by a new organization with a broader mission, called the Communicable Disease Center. Officials placed the new outfit in the region most prone to malaria, the Southeast. And to this day, as the agency has evolved in name and function, Atlanta has remained the headquarters of the C.D.C.

Today’s C.D.C. has argued that stopping evictions was within its power because — and here’s where those statistics come in — people moving around after being kicked out of their homes will tend to spread COVID-19 from state to state. The law neither specifically allows nor bars the agency from making rules about evictions. From the C.D.C.’s perspective, the logic amounts to: “Congress gave me permission to do something. The question is, did Congress give me the power to do this,” Melton said.

Melton said he believes the moratorium was both good policy and legally defensible. But he concedes it’s never been a slam dunk.

“Smart people can disagree on this one,” he said. “This one’s right down the middle of the gray zone.’’

ERIK GERMAN is co-producer of a feature-length Retro Report documentary about evictions in the wake of the COVID-19 pandemic. For more on the intersection of current events and history, visit RetroReport.org and subscribe to our weekly newsletter.