… is from pages 90-91 of the 1991 Robert Schalkenbach Foundation edition  of Henry George ‘s 1886 volume, Protection or Free Trade :
The theory of free trade may be carried into practice to the point of ideal perfection. For to secure free trade we have only to abolish restrictions. But to carry the theory of protection into practice some articles must be taxed and others left untaxed, and, as to the articles taxed, different rates of duty must be imposed. And as the protection given to any industry may be neutralized by protection that enhances the price of its materials, careful discrimination is required, for there are very few articles that can be deemed finished products in relation to all their uses. The finished products of some industries are the materials or tools of other industries. Thus, while the protection of any industry is useless unless sufficient to produce the desired effect, too much protection is likely, even from a protective standpoint, to do harm.
It is not merely that the ideal perfection with which the free trade theory may be reduced to practice is impossible in the case of protection, but that even a rough approximation to the protective theory is impossible. There never has been a protective tariff that satisfied protectionists, and there never can be.
DBx: Among the countless fallacies peddled by protectionists, none is more preposterous than is the proclamation that free trade works only in theory and not in practice while protectionism works both in theory and in practice.
In reality, while free trade is theoretically straight forward and practically not only very easily implementable but also – when implemented – successful, protectionism is theoretically contorted to the point of absurdity, and practically it only ever enriches a select few producers by furtively picking the pockets, snatching the purses, and embezzling the bank accounts of the general public.