Paul Manafort, installed as the chief strategist for Donald J. Trump's campaign after the firing of his original campaign manager, handed in his resignation on August 19 morning.
Mr. Manafort left nearly a week after a New York Times report about tumult within the Republican presidential nominee’s campaign helped precipitate a leadership shake-up. His departure reflects repeated efforts to steady a campaign that has been frequently roiled by the behavior of its tempestuous first-time candidate.