Argumentum ad National Security = appeal to the concept of “national security” (i.e. the prevention of the ultimate destruction/non-existence of the state) to justify any particular state policy (see also Niccolo Machiavelli “The Prince” for the idea that any means is justified in pursuit of the highest end, i.e. a “well-regulated republic”).
Consider the case of Socrates (all quotes are from the Apology in Plato’s Five Dialogues, translated by G.M.A. Grube).
In Plato’s Apology, Socrates is put on trial for his life on charges of “corrupting the youth” (e.g. publicly rejecting the metaphysical ideology of the polis). Thus, he faces impending death/non-existence brought on by enemies. In rejecting the various opportunities to defeat this verdict and achieve survival through a lack of “shamelessness” (page 42), i.e. pursuing unjust or non-virtuous methods, Socrates offers the following:
“Someone might say: ‘Are you not ashamed, Socrates, to have followed the kind of occupation that has led you to your being now in danger of death?’ However, I should be right to reply to him: ‘You are wrong, sir, if you think that a man who is any good at all should take into account the risk of life or death; he should look to this only in his actions…whether he is acting like a good or bad man'” (page 33).
Further, Socrates impressively turns the tables on his accusers by noting that it is they (counterintuitively) who face terrible harm by the trial:
“Be sure that if you kill the sort of man I say I am, you will not harm me more than yourselves. Neither Meletus nor Anytus can harm me in any way; he could not harm me, for I do not think it is permitted that a better man be harmed by a worse; certainly he might kill me…which he and maybe others think to be great harm, but I do not think so. I think he is doing himself much greater harm doing what he is doing now, attempting to have a man executed unjustly” (page 35).
After being convicted and condemned to death, Socrates faces those who voted for his death, stating:
“I would much rather die after this kind of defence than live after making the other kind. Neither I nor any other man should, on trial or in war, contrive to avoid death at any cost…there are many ways to avoid death in every kind of danger if one will venture to do or say anything to avoid it.” (page 42)
Now, substitute “USA” for “Socrates” and “terrorists” for “Meletus” and “Anytus”….