On a flat green peninsula beneath a towering range of sea cliffs in the middle of the Pacific Ocean, there is a hidden community of people who are isolated many times over. 

The first layer of their separation is the geographic divide of living on an archipelago with more than 2,000 miles of salt water extending in all directions. Then there is the fact of living on Molokai, a sleepy island of red clay and black lava rock and tart flowers, where there are no traffic lights and there is no movie theater. And then, zooming in once more, there is the isolation of Kalaupapa, a peninsula on the north shore of the island, thousands of feet below the rest of Molokai, that stretches out toward the Pacific.

Kalaupapa was established in 1865 as a settlement for the exile of people who had Hansen's disease, then called leprosy. More than 8,000 people died at the colony, which served as a quarantine prison until 1969. (One of the best known stories in modern Hawaii history is that of "Koolau the leper," a man who allegedly killed the policeman and three soldiers who tried to force him to leave his family and relocate to Kalaupapa.) Survivors who remain at Kalaupapa today—some forced to move there as recently as the 1940s—do so by choice. 

"I had a sense that quarantine was a practice that was going away," said Geoff Manaugh, a writer who has focused on the spatial and socio-architectural aspects of quarantine. "But as diseases become more resistant and people travel much further much faster, quarantine is becoming much more in vogue. It's not a last gasp at all, this fairly archaic approach to disease management."

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The practice of isolating sick people stretches back to the days of the Old Testament. By the 14th century, during the outbreak of the plague in Europe, governments began establishing formal quarantine protocols, according to a short history of the quarantine by PBS. During the smallpox epidemic of the 1730s, New York City residents were banished to Bedloe's Island, where the Statue of Liberty would be erected a century and a half later. When astronauts first returned from the moon in 1969, they spent three weeks quarantined in a trailer, awaiting lab results as scientists tested their blood for moon germs. (No lunar diseases were found, though it's still kind of a bummer we didn't find life up there.)

Today, as West African nations combat the worst Ebola virus outbreak in decades, modern quarantine practices are in full effect. There are specially designed suits, masks, ventilation systems, ambulance docking stations, and jets. 

Sickness-related isolation may carry the same stigmas and raise the same questions about civil liberties as it always did, and yet quarantine locations—the isolation spaces themselves—are far more integrated with the rest of society than they once were. Quarantining  someone today still means cutting them off from society, but it no longer requires sending them to an actual island. 

During the early Kalaupapa era, given the technological limitations of the time and the nascence of germ theory, any hope of an effective quarantine required physical distance. (Robert Louis Stevenson called Kalaupapa a "prison fortified by nature.") That explains why government officials banished sick people to islands. It was across the East River from Manhattan, on North Brother Island, that "Typhoid Mary" Mallon was forced to live for 24 years. Mallon was the notorious cook blamed for infecting dozens of people—three of whom died—with typhoid in the early 20th century.

The United States now has 20 quarantine stations—in major cities like Boston, Philadelphia, New York, Chicago, Atlanta, and Los Angeles—where the Centers for Disease Control and Prevention has federal authority to detain anyone they believe may have an infectious disease. (The agency makes a distinction between "isolation," which it defines as the separation of ill people to stop the spread of disease, and "quarantine, "which involves restricting the movements of well people to see if they become sick.)

Legal authority aside, government quarantines still raise all sorts of questions about individual freedoms. In fiction, Manaugh points out, "the notion of authoritarian government imposing quarantine on a terrified populations" is a recurring theme. In real life, people can be reluctant to subject themselves to an agency that might isolate them indefinitely from their families, homes, and lives. "People are not necessarily very honest when it comes to that kind of thing," Manaugh said. "Trying to break quarantine is kind of a strangely primal human instinct."

Actually, Typhoid Mary escaped her quarantine for a time. After three years of symptom-free life on North Brother Island, the city health commissioner decided in 1910 she could be released as long as she agreed never to work as a cook again. But she broke her promise and spread the disease by working again as a cook—at a restaurant, in two hotels, at an inn, in a sanitarium, and in the maternity ward of a hospital!—according to an account by Radiolab. But the curious thing about Typhoid Mary's forced isolation is that authorities went after her where several other cooks in New York, mostly men who were identified as intermittent typhoid carriers like she was, were left alone by authorities. "I think it was more about making people feel safe than making them actually safe," reporter Sean Cole told Radiolab listeners. "She was what we needed at the time."

Quarantine has always been as much about perception and the sense of security as it has been about actual safety. Which raises the question, as Manaugh put it: "Is quarantine always politically imposed?" Maybe so. The very concept of government-imposed isolation is wrapped up in all kinds of sociopolitical divisions. In Australia, Manaugh and his wife visited an old quarantine station that's since been turned into a luxury hotel. "These quarantine facilities weren't designed according to medical risk but according to class and wealth," he told me. "You'd have effectively a first-class ward… Instead of an egalitarian approach to disease you would have these weird class [divisions]."

Often when something or someone seems different for any reason, that thing or person is treated the same way as something that is dangerous—cast away, kept out. The argument could be made that quarantining a person is as much about declaring him an outsider as it is about actually stopping the spread of disease. Which helps explain why, in the story of "Koolau the leper," Koolau is seen today as the hero. The tale as it's told now is not just about a sick man who refused to be exiled, but a story that's inextricably woven into Hawaii's political climate at the time. 

Koolau was to be forced from his home in 1893, months after the overthrow of the Hawaiian Kingdom—an act perpetuated by outsiders that sought to make Hawaiians foreigners on their own land. Newspaper accounts of the time called him a murderer, a bandit, and an outlaw. But today in Hawaii, Koolau is something of a legend. And reading his story, famously fictionalized by Jack London, his resistance to quarantine resonates as a rebellion against an imposition on a much larger scale: "Because we are sick they take away our liberty. We have obeyed the law. We have done no wrong. And yet they would put us in prison."