The new Homeland Security secretary says an earned path to citizenship for the roughly 11 million immigrants living in the United States illegally is a matter of national security. It was the first time Jeh Johnson, who had little experience with immigration policy before he was appointed, had outlined his approach on the subject. The Defense Department’s former top lawyer, who worked on U.S. drone policies and helped end the Pentagon’s ban on gays in the military, said offering a path to citizenship would encourage such immigrants “to come out of the shadow, to be accountable, to participate in the...