The violence in El Paso is not about immigration policy. It is about promoting the hate, fear and division sown by President Trump. In the past three years, Mr. Trump has systematically sought to paint a hateful portrait of Hispanics. “When Mexico sends its people, they’re not sending their best,” Mr. Trump said when he announced his presidential candidacy in 2015. “They’re bringing drugs. They’re bringing crime. They’re rapists.” In 2016, he accused an Indiana-born judge presiding over cases against Trump University of being biased because of his Mexican heritage.