An allusion is a reference either to another literary work or to a well-known event, figure, ideology, etc. The title given to McCarthy’s Wheeling speech, “Enemies from Within,” alludes to a quote attributed to Abraham Lincoln: “When a great democracy is destroyed, it will not be from enemies from without, but rather because of enemies from within” (830). The quote encapsulates McCarthy’s primary argument: that America is weakened not by external enemies but by internal ones. There is no record of Lincoln having said or written those words. It is more likely that McCarthy refers to Lincoln’s Lyceum Address of 1838, which states the following:

At what point then is the approach of danger to be expected? I answer, if it ever reach us, it must spring up amongst us. It cannot come from abroad. If destruction be our lot, we must ourselves be its author and finisher. As a nation of freemen, we must live through all time, or die by suicide. (Lincoln, Abraham. The Wit and Wisdom of Abraham Lincoln. Edited by Alex Ayres. New York: Meridian Group, 1839.)

Besides dovetailing with McCarthy’s claims about The Threat of Betrayal from within, the allusion to Lincoln rhetorically links McCarthy to a well-respected president popularly understood to have regretted the necessity of war.