Here’s a letter to the New York Times:
Unimpressed that wage flexibility creates jobs in Texas, Paul Krugman writes that “at a national level lower wages would almost certainly lead to fewer jobs” (“The Texas Unmiracle ,” August 15).
By asserting – for he has no evidence – that job growth in Texas comes at other states’ expense, Mr. Krugman reveals his Keynesian confusion.
But he can be forgiven, for Keynes himself was deeply confused. While it’s true that in some parts of the General Theory  Keynes alleges that falling nominal wages won’t increase overall employment, in other parts of that book – parts in which Keynes more carefully spells out his assumptions – he sings a different song. Consider Keynes’s conclusion on this matter from page 253 in Chapter 18: “If competition between unemployed workers always led to a very great reduction of the money-wage level … there might be no position of stable equilibrium except in conditions consistent with full employment…. At no other point could there be a resting-place.”*
Translation: “If wages are flexible, competition for jobs will reduce nominal wages until there is full employment.”
Keynes himself here contradicts his modern-day St. Paul.
Donald J. Boudreaux
As the late David McCord Wright  pointed out about Keynes’s General Theory (in addition to the fact that it is no general theory at all):
about half of the General Theory is inconsistent with the Keynesian model, usually understood. The General Theory is almost, in fact, two separate books only slightly related by a common terminology.
This quotation from Wright is from page 83 of his superb article “Is There a Keynesian System?” found in Money, the Market, and the State: Economic Essays in Honor of James Muir Waller , N. Beadles and L. Drewry, eds. (Athens, GA: University of Georgia Press, 1968), pp. 82-90.
More generally, Mr. Krugman’s take on Texas is questionable – as Kevin Williamson explains . (HT Peter Minowitz)