WASHINGTON — A former top Watergate prosecutor, expressing impatience with the pace of Robert Mueller’s Russia probe, says the Justice Department special counsel should move “promptly” to file a report on President Trump’s conduct and stop “letting this thing drag on.” “I think it’s in the national interest to move promptly to bring this matter to a head,” said Philip Lacovara, who served as senior counsel to Watergate special prosecutors Archibald Cox and Leon Jaworski, in an interview with the Yahoo News podcast “Skullduggery.” “I think the public deserves to know — to put a riff on President Nixon’s comments...