In 1938, just three years after the NLRA’s passing, the Supreme Court ruled in its Mackay Radio decision that while workers could not be fired for striking, they could be permanently replaced. Under the Mackay doctrine, as it came to be called, if workers struck for economic gains like raises and improved working conditions, the employer could hire permanent replacements—scabs, as they are otherwise known—and then not have to give the workers their jobs back when the strike was over. For workers, the difference between the terms fired and permanently replaced was of little importance if both meant they were out of a job. After a short curve of learning how to wield this new crushing tool, bosses realized that, since they can hire scabs to keep production moving during a strike, there is little incentive to reach an agreement with current employees at the bargaining table.