There is, they believe, a pathway to freedom: Renounce these contracts or otherwise assert your sovereignty. (Mr. Morton said he once told the Social Security Administration, “I don’t want this number.”) Then no one — not the taxman, not the police — can tell you what to do. Not all sovereigns are con men, but their belief system lends itself to deceit. You might declare yourself a “diplomat” from a nonexistent country. (Mr. Morton represented the Republic of New Lemuria and the Dominion of Melchizedek.) Or start a fake Native American tribe. Or blow off a court case because the American flag in the courtroom has gold fringe. Some sovereigns have even lashed out violently at law enforcement officers, which is why they’re considered a domestic terrorism threat.

Many sovereign myths hark back to the creation, in 1913, of the Federal Reserve. “It was this weird, complicated instrument for controlling the monetary system. People saw it as sinister,” the author J. M. Berger told me. In a recent paper, Mr. Berger traced the circulation of these ideas, in part, to a company named Omni Publications, which was something like the Infowars of the middle of the 20th century. One Omni title, “The Federal Reserve Conspiracy,” claimed that “enemy aliens” had infiltrated the banking system, and that their biographies could be found in “Who’s Who in American Jewry.” (Sovereign lore is often rooted in anti-Semitism.) By the 1970s, the intellectual father of the sovereign citizen movement, William Potter Gale, helped spread this type of falsehood to a larger audience.

The founder of the antigovernment group Posse Comitatus, Mr. Gale aligned himself with an emerging movement of tax protesters who argued, for instance, that paying taxes was a form of involuntary servitude. In turn, he introduced them to his warped version of America, where patriots establish their own legal system and hang those who defy it. Mr. Gale’s specific gift was wrapping nonsense in enough legalese that it sounded real. “If you have this movement that offers you essentially a lot of magic words that you can say to get out of trouble, that’s going to really appeal to people who are desperate and angry,” Mr. Berger said. Mr. Gale’s outreach was a success. Over time, the line between thousands of tax protesters and Posse members blurred.

Take “redemption” — a theory popularized, in part, by a Gale associate. Remember how the corporation-slash-fake-government used us as collateral? According to sovereign lore, this means the government set up secret accounts in our names. Some believe they contain the oddly specific amount of $630,000. (To be clear, this is “pure fantasy,” according to the Internal Revenue Service.)

One way sovereigns try to make the imaginary money real is by abusing legitimate I.R.S. forms. Law-abiding taxpayers use Form 1099-OID, for example, to report “original issue discount” income. But some sovereigns write in fake OID income, and fake withholding, in order to claim illegitimate refunds. If you file such a return, you risk at the very least a large fine. Yet from 2012 to 2014, according to the Treasury Inspector General for Tax Administration, the I.R.S. received close to 7,000 sham OID filings.

Chronically underfunded and understaffed, I.R.S. investigators refer only about two dozen sovereign-scam cases, on average, for prosecution each year. The agency sometimes misses returns that should raise suspicion. For example, in 2016, the I.R.S. discovered a sizable redemption scheme — but only after processing 207 bogus returns and disbursing more than $43 million. That’s another reason these strange theories persist, and have begun to leach out of the sovereign network and into the general population: Sometimes, improbably, they work.

2. ‘They just went berserk’

Mr. Morton was born in 1958, and his comfortable childhood in Northern California was a tutorial in how to make a sales pitch. His mother, Maureen Kennedy Salaman, was — as San Francisco magazine once described her — a “millionaire evangelical alternative-medicine fanatic” who promoted questionable cancer treatments.