The sum and substance of the "Keynesian Revolution" was the thesis that there can be an unemployment equilibrium on the free market. As we have seen, the only sense in which this is true was known years before Keynes: that widespread union maintenance of excessively high wage rates will cause unemployment.

"Social Income, Expenditures, and Unemployment," §1 of "Hoarding and the Keynesian System," §F of "The Demand for Money," §5 of "Money and its Purchasing Power," ch. 11 of Man, Economy, and State: A Treatise on Economic Principles (orig. 1962), contained in Man, Economy, and State with Power and Market, Scholars Edition (2nd ed.) (Auburn, AL: The Ludwig von Mises Institute: 2004, 2009), p. 783.