“When the president travels overseas, the Secret Service will bring along a polygraph examiner in case they need to determine quickly whether someone acting suspiciously is intent on doing harm.” So note Marc Ambinder and D.B. Grady in a parenthetical remark at p. 164 of their new book, Deep State: Inside the Government Secrecy Industry.
But as emeritus professor of psychology John Furedy has observed, polygraph operators can no more divine truth from the examination of polygraph charts than ancient Roman haruspices (entrail readers) could divine future events from the examination of intestines. Make believe science yields make believe security.