There were also a few self-financed political campaigns, including some fruitless races in the Virgin Islands. In his 2012 run, Mr. Mosler said he believed the voting was rigged. He made a vanity run for Senate in Connecticut in 2010 as an independent, making waves by offering to use $100 million of his own money to pay down the deficit if any member of Congress could prove that government spending was actually constrained by tax revenue. He came in third, with about 1 percent of the vote. “It was a mistake,” Mr. Mosler said of running in Connecticut. “It did get the ideas out there, though.”

Mr. Mosler started his career at a small bank in Connecticut, and eventually became a Wall Street trader. It was there, he said, that he developed an intuitive understanding of how the economy works — one very different from that of policy makers in Washington and the vast bulk of academics.

“All debt management is, is debiting and crediting different accounts,” Mr. Mosler said, recalling seeing numbers appear and disappear from his computer at Bankers Trust in New York in the 1970s. “Can the federal government run out of dollars? No, because the Fed could pipe in a bigger number. That number doesn’t come from anywhere. It’s like when a player scores a field goal at a stadium. Three points just appear. The government is just the scorekeeper for the dollar.”

In the early 1980s, he left Wall Street and along with a partner, Clifford Viner, who is now the owner of the Florida Panthers hockey team, founded a hedge fund in Boca Raton, Fla. The fund made relatively few, relatively complicated financial bets, said Michael Reger, a partner of Mr. Mosler’s for the last 20 years. “He’s an urban myth,” Mr. Reger said of the affable, talkative and bookish Mr. Mosler.

Mr. Mosler’s fund has made a number of bets informed by his theory. For instance, Mr. Reger said, when the Treasury was paying down the United States debt during the Clinton years, many bond traders thought that prices would spike because of increasing scarcity. But Mr. Mosler predicted that no such scarcity would ever materialize, and shorted the bonds.

That trade panned out, though others have not. The business lost hundreds of millions of dollars betting that Russia would not default on its debts. That country’s fixed exchange rate spurred it to go belly up, Mr. Mosler said.