Great changes in strategic and tactical approaches develop slowly. They are most often the product of a long line of evolutionary development which includes not only phases of slow growth but leaps and giant forward strides.
The first such struggle was for the right "to think unthinkable thoughts," to think of organizing the workers. It had been regarded as a conspiracy--any combination of workers to organize a union, even to conduct meetings, had been regarded as illegal.
That won, the next struggle was over the right to openly proclaim the need for organization and the right to strike. But the thing to remember is that the strikes came before striking was legalized. That's the lesson of the 1930s. The great sit-down strikes, which were the heroic age of modern labor organization, came first. Then came the law that validated collective bargaining, the Wagner Act.