April 2015 is the month that conservative populism broke out and reached the major leagues of American politics. On April 15, the editors of the New York Times felt compelled to denounce a Washington Post op-ed by Senator Jeff Sessions (R., Ala.), in which he called for reduced immigration to help raise the wages of American workers. The Times editors were particularly miffed that “Mr. Sessions accuses the financial and political ‘elite’ of a conspiracy to keep wages down through immigration” (“elite” is put in sneer quotes, as if there were no elite). What is important to note is not...