Step one: Find an expert with an impressive-sounding academic title to legitimize shoddy advocacy propaganda. Meet Brian Levin. He's the one-man band behind something called the "Center for the Study of Hate and Extremism" at California State University, San Bernardino. The "center" (that is: Levin) claims to be "nonpartisan" and "objective." But he is a former top staffer of the militant, conservative-smearing Southern Poverty Law Center, which was forced to apologize earlier this year after including famed black neurosurgeon and GOP 2016 candidate Ben Carson on its "extremist watch list" of hate groups. At SPLC, Levin infamously posited that the...