Mr. Marche is the author, most recently, of “The Next Civil War.” He wrote from Toronto, where he lives. You may not think of Chubby Checker’s “Let’s Twist Again” as an incendiary political anthem, or ...

If you were to base your entire knowledge of American current events solely on the social media feeds of the Department of Homeland Security (DHS), you could easily conclude that the U.S. is at war.