… is from page 93 of Benjamin Rogge’s 1952 talk titled “Economists as Freedom Fighters,” as the text of this talk is reprinted in A Maverick’s Defense of Freedom, the 2010 collection of Rogge’s essays edited by Dwight Lee:
I submit further that the great virtue of the free market type of economic organization is not its tested ability to bring a high level of living to those who work under it; rather, it is that it is the only type of economic organization which is consistent with the maintenance of those individual liberties which are to be prized more dearly than the material benefits of an efficient economy.