Woodward & Bernstein
This two were relatively unknown reporters to most until they broke the biggest story in American politics, regarding the Watergate Scandal. They listened to the long time unnamed source known as "Deep Throat" who agreed to give them all of this information about the whole scandal as long as they promised not to name him, because he was rightfully afraid of what might happen to him.
Mark Felt (Deep Throat)
Mark Felt, known as Deep Throat until just before he died, was the most important piece in unveiling the corruption we know as the Watergate Scandal.
President Nixon as we know, ordered his men to sneak into the Watergate Hotel where his rather weak opponent kept his files about his campaign. Nixon was heavily favored to win the presidential campaign, and in the end he won by one of the largest victories besides George Washington's unopposed run.
Sam Ervin organized the "Ervin Committee" which was in charge of investigating the Watergate Scandal. In 1954, Nixon actually appointed Sam Ervin to organize the committee to investigate Joe McCarthy, which later came back to haunt Nixon during his presidency, causing him to resign.
This man was the first to testify against Richard Nixon, being the catalyst to other's who would come forth to testify after him.
Colson was the White House counsel specializing in political affairs during Nixon's presidency and is reported to have said "I'd walk over my own grandmother to re-elect Richard Nixon."
Haldeman was not only the White House Chief of Staff, but also a very close friend of Nixon's, who Nixon had loved like a brother. And, fun fact: Haldeman was known as "The Brush" due to his oh-so-stylish haircut
He was in charge of domestic affairs during Nixon's presidency. He also created the infamous "plumbers" group.