After The Washington Post broke the news of the Watergate break-ins in 1972, the Nixon administration circled the wagons. And in 1997 – a full 25 years after the fact – Katherine Graham, who was with The Post in 1972, vividly recalled how “Nixon began making threats of economic retaliation against the paper.” According to Graham, Nixon bullied the paper, sought to silence it, and launched a “campaign to undermine public confidence in [it].” Judging from what Graham said, it appears that Nixon wanted to be sure people understood that if they continued to pry into Watergate or talk about...