It started in Cleveland. Workers at General Motors’s Fisher Body shop were sick of the company’s attempts to cut their wages. The shop was particularly restive, a hotbed of support for the recently chartered United Auto Workers (UAW) — the mammoth auto corporation had laid off many of the workers at Cleveland-Fisher in hopes of weakening the budding organization. On the morning of December 28, 1936, a committee of union men was scheduled to meet with the company to discuss the workers’ myriad grievances. But at the last minute, the company rescheduled for the afternoon.

“A grievance of the strongly organized quarter panel department was to have come under discussion,” wrote UAW organizer Henry Kraus in The Many and the Few, his history of the union’s foundational years. “When these fellows heard of the postponement they said: ‘To hell with this stalling,’ and yanked the power off. The steel stock, metal assembly, and trim departments followed suit in rapid succession and in a few minutes the whole plant was dead.”

The strike was on. But rather than a traditional walkout, with picketing outside the plant gates, the workers sat down inside and refused to leave. The tactic was an innovation, one that was growing in popularity. Autoworkers knew that their ability to shut down GM production was the source of their power, but in an era of rampant, sometimes deadly, police brutality against organizers, a traditional picket line was no sure thing.

Picketing would open them up to violence (not to mention winter weather, which could be as demoralizing as any police squadron). There was no telling how long a regular picket line would hold or how effective it might be in keeping scabs from operating the company machinery. But inside, their proximity to valuable equipment that GM was loath to endanger with any police offensive protected them.

The UAW needed a breakthrough, and they needed it quickly. Despite the auto industry’s massive workforce — more than two hundred thousand workers at GM alone — the union was puny. On Detroit’s West Side, where many of the industry’s small parts and supply shops were located, a young, ambitious organizer named Walter Reuther headed a local that had fewer than one hundred members in 1936. This, even as the city’s auto giants employed some 250,000 autoworkers.

The electoral victory of Franklin Delano Roosevelt (FDR) that year had demonstrated workers’ desire to demand more — FDR was no champion of the working class when he first ran for the presidency in 1932, but four years later, in accepting his party’s nomination, he was criticizing the “royalists of the economic order.” He dominated at the polls in industrial centers like Flint, Michigan, and workers took his win as proof that they could go on the offensive: shortly after the election, there were seven work stoppages in one week.

If labor was to have a breakthrough, now was the time, and GM, employing more autoworkers than any of its rivals, had to be the place. The union just needed to find a way to force the company into a national agreement.

Bob Travis, a young organizer from Toledo, Ohio, where he had seen the citywide general strike that erupted after workers walked off the job at Toledo Auto-Lite, was the sit-downers’ UAW man on the outside, the strategist. The union had members inside the plants, but those leading the strikes were rarely union men. The outrage was ahead of the UAW. As such, the union gave Travis its blessing to set up a network of organizers in the company’s plants, readying them to capture the next spark and grow it into a roaring flame.

“Boys,” Kraus recounts Travis telling his organization of GM workers that fall, “the whole future of the Flint workers depends on you. In fact I can truthfully say that the fate of the autoworkers throughout the country rests on your shoulders. I know you’re not going to let them down. Whatever happens stick together. Don’t leave the shop under any circumstances. And remember — nobody gets fired.”

Two days after the Cleveland-Fisher sit-down began, workers at Fisher One noticed that the company was moving the plant’s all-important dies, used to stamp car bodies, out of the plant. Suspecting GM was taking measures to undercut organization and perhaps ship jobs permanently out of Fisher One, they were eager to take action. At a lunch time meeting with the workers that filled the union hall, Travis prepared the ground.

“Boys,” the union organizer said, “I’m not going to tell you what you ought to do. That ought to be plain enough to you if you want to protect your jobs. In my plant in Toledo, General Motors walked off with 1,500 jobs a year ago and in Cleveland the Fisher Body boys struck just Monday to save theirs. What do you want to do?”

The hall resounded with cries of, “Shut her down! Shut the goddamn plant!” With that, the war was on. The workers rushed back to the quarter-mile-long building and moments later, they flung open a third-floor window, exclaiming to Travis that the plant was theirs.

The sit-down would spread to several other GM body plants, and the workers ultimately forced the company to the negotiating table. On February 11, 1937, the two sides reached an agreement, with the company recognizing the UAW as the members’ exclusive bargaining agent. In total, the strike lasted forty-four days, idling some 136,000 GM workers and causing upward of a quarter-million cars to go unbuilt.