He was an idealistic 34-year-old prosecutor from Vermont who came to Washington in the wake of the Watergate scandal. Now, after eight terms in Congress, Senator Patrick Leahy is retiring, at a time when Congress, he says, is more bitterly divided than ever. The fourth-longest serving senator in U.S. history – his tenure bookended by Nixon’s political coverup and Trump’s insurrection – talks with correspondent Robert Costa about the role of the Senate and the dangers of partisanship.