President-elect Donald J. Trump on Wednesday chose Tulsi Gabbard, a former Democratic congresswoman who became one of his most enthusiastic backers, to serve as the director of national intelligence. Ms. Gabbard, a lieutenant colonel in the Army Reserve who served in Iraq, has been a longtime critic of the foreign policy establishment. Her nomination is another sign that Mr. Trump intends to give top foreign policy jobs to supporters who are deeply skeptical of the effectiveness of U.S....