Five men broke into the Democratic National Committee’s headquarters in 1972, and just two years later, President Richard Nixon teetered on the brink of impeachment before resigning as the President of the United States. That’s the short version. The longer version involved two Washington Post reporters, Bob Woodward and Carl Bernstein, who performed some of the most critical investigative journalism in American history. Watergate, as it became known, illustrates the importance of a free press as conceived in the First Amendment of the Bill of Rights of the U.S. Constitution. It is a prime example of media operating as a check on governmental power and excess.

Bob Woodward’s career at the Post had begun as a failure. He was given a two-week tryout by the Metro section in 1970, but none of his stories were published. Woodward headed to the Montgomery Sentinel, where he honed his reportorial skills and joined the Post a year later. His future reporting partner, Carl Bernstein, followed a more traditional career path. He started in journalism by taking a job as a copyboy for the Washington Star at 16; joined the Elizabeth Daily Journal in New Jersey; and then headed back to D.C. to write for the Post in 1966. There he covered police and the courts, which is why he was assigned the story of five men arrested for breaking into the DNC headquarters on June 17, 1972. So the now-famous team of Woodward and Bernstein started to investigate a massive conspiracy.

The break-in at the DNC headquarters was part of a wiretapping scheme meant to help Nixon stay in the Oval Office. Members of the Committee for the Re-Election of the President (CRP) wanted to listen in on and record the Democratic Party’s phone conversations. This was before spying could be accomplished with little technical knowledge; surveilling the DNC required a group of former CIA and FBI agents to bug office phones. That’s why they had to break into the Watergate Complex.

The men were caught when a security guard named Frank Willis noticed that door latches had been taped over. He called the police, the men were arrested, and the Post assigned the story to Woodward. Police sources told Woodward the break-in seemed like a professional operation because the men carried thousands of dollars and wore surgical gloves to cover their fingerprints. Shortly afterward, Bernstein began working on the story, and later discovered that one of the burglars had deposited a $25,000 check from Nixon’s re-election campaign.

Things got stranger after an anonymous source known as “Deep Throat” (the title of a popular porno movie) became part of the story. Deep Throat, a high-level government source, provided Woodward information on the FBI’s investigation into the Watergate break-in, pointed him toward other leads, and otherwise assisted with the duo’s reporting. Woodward kept his source’s identity secret from everyone, including Bernstein and his editors, until the source revealed himself to Vanity Fair more than thirty years later in 2005. Deep Throat turned out to be then-deputy director of the FBI, W. Mark Felt. Woodward never revealed Felt’s name to anyone, including his editors and his Washington Post colleague, Bernstein. (Nowadays, most publications would insist that editors know the identity of a major source like this.)

Felt and Woodward had met in 1970, a couple of years before the DNC wiretapping scheme. They frequently spoke on the phone, and Felt provided tips on other stories, but their relationship changed in the aftermath of the burglary. Felt originally provided sparse, off-the-record details about Woodward and Bernstein’s discoveries then stopped taking Woodward’s calls.

That’s because Nixon and his advisors had no intention of letting the Watergate scandal end his shot at re-election. They conspired to cover up the break-in, even though Nixon probably didn’t have any involvement in the actual precipitating crime. Nevertheless, he tried to prevent the FBI from learning the truth. Felt couldn’t accept this. He wanted people to know that Nixon’s White House was corrupt while protecting the agency he loved. At great risk to his career, Felt transformed himself into the almost mythical figure of Deep Throat.

But he didn’t make it easy. He made the young Post reporter play spy. They set up an elaborate system to indicate when they should meet. Woodward could move a flowerpot with a red cloth flag on his porch to get Felt’s attention; Felt would circle page 20 of the daily New York Times and draw the hands of a clock to show he had something to share. Once the signals were given, the two would meet in a parking garage that night.

The games didn’t end there. Woodward had to take a specific route to the parking garage. He wasn’t allowed to just walk off the front step and head straight to the meeting. Instead, he had to leave his building from a different exit than usual; walk down an alley; take a taxi to a busy hotel; get in another taxi; and then head to the parking garage. This rigmarole was designed to prevent anyone from learning how Woodward got his information about what really happened in the Watergate scandal.

The Post published more than 300 stories about the Watergate scandal. But Woodward and Bernstein made two key findings: Attorney General John Mitchell controlled a secret Republican “slush” fund of between $350,000 and $700,000 to spy on Democrats, and the FBI had discovered White House officials and members of Nixon’s reelection committee conducting a “massive campaign of political spying and sabotage” of which the Watergate scandal was but one part.

Woodward and Bernstein were the personification of persistence. Washington Post executive editor Ben Bradlee said the reporting duo had “no qualms about calling a source back and back and back” to learn something new as Bradlee enforced a double confirmation rule, where every fact had to be verified by two sources. Once they found something, Bradlee said, they pushed to provide more sourcing and documentation to ensure their reporting was accurate. Doors slammed in their faces, and sources hung up on them. Some issued threats against the two young reporters, the Post and its publisher, Katharine Graham, and everyone else involved in the story.

Click here to watch the original TV broadcast of Nixon resigning.

Meanwhile, investigative journalist Seymour Hersh was conducting his own reporting into the DNC break-in for the New York Times. Hersh believed the Post had too much of a head start and too many sources for the Times to compete. But he was assigned the story in December 1972, and shortly after, revealed that the one of the burglars had received a payment from the Committee to Re-elect the President.

Woodward, Bernstein, and Hersh’s reporting changed the nation. By the time it was over, Nixon had to assure the nation that he wasn’t a “crook” and there were the famous Watergate Hearings, which were broadcast live on television for months, riveting the nation. Nixon found himself heading towards impeachment. What had appeared to be a simple burglary had devolved into cover-ups, corruption, and ultimately a president forced to resign on August 9, 1974. Nixon might have faced criminal charges if his vice president (and then successor) Gerald Ford hadn’t issued a full pardon, thereby dooming his own reelection chances two years later.

Afterward, applications to journalism schools hit all-time highs. Not that everyone paints so rosy a picture: critics say the media’s role in ousting Nixon is overstated, and Bernstein himself said the Watergate scandal’s effect on journalism was short-lived. Either way, Woodward and Bernstein are household names even today. How they reported on the Watergate scandal—finding sources, using them to unearth new facts, and keeping their confidence for 33 years—established a model that is still followed today.