By 2020, the American government, reacting to serious social and economic problems, created a series of districts within most cities where the unemployed, the mentally ill, and other outcasts were interned. This internment, in fact, amounted to nothing less than imprisonment.
Physically, the Sanctuary Districts were what used to be run-down neighborhoods of major cities, which were closed off by erecting cement perimeter walls, literally separating the rich from the poor. If someone could not provide ID and proof of employment, they would be forcibly relocated to the Sanctuary District. Typical processing of internees consisted of response to a questionnaire to determine whether the internee was a 'dim' (mentally ill), or a 'gimmie' (unemployed). Despite these slang classifications there was little difference in how internees were treated once they were processed into the camps. A resident that turned hostile in the district was called a 'ghost'.
While originally established with benevolent intent, conditions inside the camps had quickly degenerated to the point that by 2024 over-crowding was chronic, and the Sanctuary Districts had become essentially debtors' prisons. Food was rationed, but even with those measures there were regular shortages. Additionally, medical treatment, both physical and mental, was inaccessible, and the threat of physical violence from other inmates or the cynical and hardened guards was a constant threat. Even so, many people seeking to hide from law enforcement, creditors, or other social elements sought to lose themselves in the hidden depths of the Sanctuaries, often aided by the administrative staffs who felt sympathy for them, despite the conditions of the camps. The upper classes of the United States had convinced themselves that they had solved their nation's social and economic problems, with the Sanctuary Districts serving as a means to "sweep under the rug" people who were suffering economically, and simply ignore them.
On September 1, 2024, after weeks of unrest and violence, residents of Sanctuary District A in San Francisco took over an administrative processing center, holding six employees hostage and gaining access to the planetary computer network in order to broadcast their stories to the world.
The Bell Riots, as they were later named, after protest leader Gabriel Bell, ended when the governor of California ordered federal troops to retake the processing center by force. Hundreds of sanctuary residents were killed, including Bell himself, although none of the hostages were harmed.
In the wake of the Bell Riots and the senseless deaths of so many people, American public opinion turned against the Sanctuary policy, and the districts were abolished. (DS9: "Past Tense, Part I", "Past Tense, Part II")