When it comes time to protecting the homeland, the United States of America must be right 100 percent of the time. And the enemy, which desires to strike us again, only has to be right once.
Now we will no longer concede so easily that anyone has the truth; the rigorous methods of inquiry have spread sufficient distrust and caution, so that we experience every man who represents opinions violently in word and deed as any enemy of our present culture, or at least as a backward person. And in fact, the fervor about having the truth counts very little today in relation to that other fervor, more gentle and silent, to be sure, for seeking the truth, a search that does not tire of learning afresh and testing anew.
A king may be a tool, a thing of straw; but if he serves to frighten our enemies, and secure our property, it is well enough; a scarecrow is a thing of straw, but it protects the corn.
The end and aim of spying in all its five varieties is knowledge of the enemy; and this knowledge can only be derived, in the first instance, from the converted spy. Hence it is essential that the converted spy be treated with the utmost liberality.