RoyCohnpersonifiedthedarkartsofAmericanpolitics,turningemptyvesselsintodangerousdemagogues-fromJosephMcCarthytohisfinalproject,DonaldJ.Trump.Thisthriller-likeexposéconnectsthedots,revealinghowadeeplytroubledmastermanipulatorshapedourcurrentAmericannightmarebbb