“The political horizon would be greatly clarified if the voters were offered the choice of three parties representing three strategies: A conservative party committed to the preservation of individualism, perhaps in a highly modified form; a communist party bent upon revolutionary changes through violent seizure of power, confiscation, and a proletarian dictatorship; and a radical party seeking to socialize the basic industries and to move toward an equalization of economic privilege through purchase, taxation, and drastic regulation, without resorting to confiscation or armed seizure of power.”