In the U.S. this week, declassified FBI documents revealed that the U.S. government conducted a wide-ranging investigation into Gerard Damiano, director of the 1972 porn film Deep Throat. The heavily redacted documents showed that FBI agents across the nation were directed by top figures at the agency to conduct a campaign of harassment and intimidation against Deep Throat producers and distributors in a deliberate effort to stem the tide of sexual freedom that was sweeping the nation. Records show they seized prints of the film, and questioned everyone associated with its distribution, from delivery boys to theater managers.

Included in the stack of documents is an August 1973 letter stating that Damiano was being considered for prosecutorial immunity. The papers don’t say what crime exactly Damiano had committed, but at the time the film was thought to violate obscenity statutes and, because of an assumed link between porn and organized crime, various RICO charges might also have been considered. Ironically, the second-in-command at the FBI at that time was Mark Felt, who would soon play Deep Throat in real life when he became a secret source for Carl Bernstein and Bob Woodward during their Watergate investigation into Republican Party corruption. He adopted the moniker Deep Throat as his code name, and his real identity remained a mystery until he came forward in 2005.

Despite the FBI’s efforts, the tides of cultural change were too strong. What had been universally offensive just a generation before was seen as entertaining in 1972, and Deep Throat became the most popular x-rated film ever released, eventually earning more than 300 million dollars after an initial investment of around $25,000. At the height of the Deep Throat craze, the film was booked into mainstream cinemas and moviegoers attended packed showings without an iota of shame. Since then American culture has changed again, and, though consumption of pornography is so widespread it generates untold billions of dollars in yearly revenue, it has lost its aura of respectability and is virtually always consumed in private.

Famed whistleblower Mark Felt aka Deep Throat died yesterday of heart failure in Santa Rosa, California at the age of 95. In 1972 Felt was instrumental in helping Washington Post reporters Bob Woodward and Carl Bernstein break open the infamous Watergate scandal, which remains one of the most important events in American history.

At the time, Felt was an FBI operative frustrated by the slow pace of investigation into a break-in at Democratic Party Headquarters at Washington, D.C.’s Watergate Hotel. It seemed clear to him that Republican operatives—possibly directed by President Richard Nixon—were likely involved, and that they were sabotaging the FBI investigation. Felt took matters into his own hands by secretly meeting with Bob Woodward during the Post’s investigation of the crime.

At these meetings, which took place in the dead of night in a Virginia parking garage, Felt gave Woodward crucial FBI information. They agreed that Felt’s identity could not be revealed, and that was when Woodward coined the Deep Throat moniker. Felt coined his own immortal phrase: “Follow the money.” That advice helped keep Woodward and Bernstein moving in the right direction during their investigation, and today is a mantra for investigative reporters seeking the truth behind political scandals, as well as an almost universal insight into human motivation.

When the Watergate scandal broke, Nixon resigned the presidency rather than be impeached. The event is often cited as the first major blow to the American public’s belief that their presidents were incorruptible. In that way, Mark Felt helped usher in an age of political cynicism. When he finally revealed his true identity in 2005, the Watergate saga was replayed and he was criticized and praised anew for his role. But whether hero or traitor, he is without question one of the most important Americans of his time.