WASHINGTON — A lawyer for President Trump broached the idea of Mr. Trump pardoning two of his former top advisers, Michael T. Flynn and Paul Manafort, with their lawyers last year, according to three people with knowledge of the discussions. The discussions came as the special counsel was building cases against both men, and they raise questions about whether the lawyer, John Dowd, who resigned last week, was offering pardons to influence their decisions about whether to plead guilty and cooperate in the investigation. The talks suggest that Mr. Trump’s lawyers were concerned about what Mr. Flynn and Mr. Manafort...