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.