Following the labor upsurge and radicalization that came in the wake of World War I, workers’ militancy tailed off, and the 1920s saw the American capitalist class at the peak of its power, confidence, and productiveness, in total command of industry and politics. Manufacturing productivity rose more rapidly during this decade than ever before or since, the open shop (which banned union contracts) prevailed everywhere, the Republican Party of big business reigned supreme, and the stock market broke all records. [...]
What transformed the political landscape beyond recognition was the outbreak of what Rosa Luxemburg would have called a “mass strike upsurge,” a phenomenon she had witnessed and analyzed at the time of the 1905 revolution in Russia and the accompanying wave of mass strikes. Out of the blue, starting in Detroit auto plants in spring 1933, you got a series of ever larger and more encompassing strikes, mobilizing ever broader groups of workers on the shop floor and the streets — organized and unorganized, employed and unemployed, in an ascending wave. Programmatic demands and ideas that seemed pie in the sky were now, with the increase in workers power, plausible and actionable. [...]
Equally important, the smashing victories in the 1934 strikes endowed the nascent radical-led labor movement with the confidence and capacity to organize the United Auto Workers (UAW) and the CIO over the next three years. Roosevelt was transformed from a standard politician into a reformer, the carrot and stick of the new labor movement inducing the administration to advocate a series of historic sociopolitical reforms that included the Social Security Act, the Fair Labor Standards Act (which set maximum hours and minimum wages for most workers), and the Wagner Act (which extended union recognition and set up routinized collective bargaining). [...]
To put the point in a more general way, an electoral strategy of voting for a third party could never be sustained, as the right-wing party would typically win greater electoral majorities as the third party increased its vote share. Only if the third party could achieve a majority all at once, perhaps on the back of a titanic mass movement that brought about a sudden lurch to the left among a large section of the citizenry, would it have a chance of succeeding. Otherwise, dull electoral calculation ensures the hegemony of the two-party monopoly.