"Perpetual Warfare" is not a new concept, not a unique concept to America. But — for a government — it is “useful”.
The direct function of Never-ending "Perpetual Warfare" is to support & maintain the Military-Industrial Complex. (The one that General & then President Eisenhower, a Republican, warned us about.)
The "justification" for such Never-ending support of the Military Industrial complex is two-fold:
 It is fed, propagandistically, to the public as being about "defending" something — sold as a "defensive" response (although, in actuality, it may be an offensive rather than defensive action; and,
 it "creates jobs". This last ("job-creating") function, however — when it is used as a primary justification — unless a country is at Full-On Wholesale World War — indicates a WEAK economy, rather than a strong one.
The term #terrorism is a highly-maleable & flexible term. Its use (now) is liberal. Its application is ALWAYS relative to the center-of-power using the term. And its propagandistic function cannot be over-estimated. In its true sense, terrorism does exist. But it’s #MEANING (both explicit & implicit) depends on WHO is talking, and whom they are talking to. The meaning of the word, in other words, is #relative.