Within weeks of its legalization, Solidarity's membership exploded to nearly 10 million workers.

The growth was staggering. Following its formal registration in late 1980, the union quickly united thirty-six regional groups. Almost overnight, eighty percent of Poland's state employees joined, including many rank-and-file Communist Party members. By early 1981, Solidarity represented ten million people. This massive, peaceful mobilization created a powerful alternative civic space. It completely undermined the regime's ideological claim to rule on behalf of the working class.