In 1914 the Colorado Coal and Iron strikes—lead by the unions at the time—came to a head which resulted in the Ludlow Massacre and the Ten Days War. It involved a long-running strike of 10-12k miners.
The anti-union NYT reported in the day that the actions against the miners were "worse than the order sent to the Light Brigade into the jaws of death, worse in its effect than the Black Hole of Calcutta."
They lost the strike, brutally, but part of the result was the 1935 NLRA.
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