How media created the very climate of hate they sought to preempt. The arrest of a Jewish American-Israeli teen for making hundreds of bomb threats against American Jewish institutions in recent months seems to put paid to the favorite explanation advanced by both American Jews and the broader American left–i.e., that Donald Trump’s election empowered right-wing anti-Semites, leading to an upsurge in anti-Semitic acts. Yet the fact remains that the number of threats did jump dramatically following Trump’s election, to a degree that seems hard to attribute to mere coincidence. Now, new disclosures by the Israeli police provide a way...