Editor's note: The article first appeared on Constitution Daily in 2013 during the 40th anniversary of the Watergate scandal.

Forty years ago, when President Richard M. Nixon fired Watergate Special Prosecutor Archibald Cox on October 20, 1973 in the infamous “Saturday Night Massacre,” seeking to shut down Cox’s criminal investigation before it proved Nixon’s complicity in the Watergate cover-up, the nation’s system of laws hung in the balance.

Archibald Cox

At issue was whether the President of the United States, by dint of sheer force, could overpower the rule of law and halt an investigation of his own conduct as Chief Executive, thus defying the Special Prosecutor’s office, the courts, Congress, and 19 ordinary citizens of the federal grand jury who had directed Nixon to turn over nine White House tapes that would prove or disprove his involvement in a criminal cover-up.

Archibald Cox, a mild-mannered Professor of Constitutional Law at Harvard Law School, had no prosecutorial experience before being tapped to serve in the no-win position of Watergate Special Prosecutor. Yet Cox had established a reputation as a highly-principled lawyer of impeccable integrity. He was a direct descendant of Roger Sherman – signer of the Declaration of Independence and the Constitution. He was an early law clerk to the famous Judge Learned Hand of the federal court in New York. He was a labor advisor to the young Senator John F. Kennedy of Massachusetts; head of JFK’s “Brain Trust” during the 1960 campaign; and Solicitor General in the Kennedy Administration, arguing many of the landmark civil rights cases of modern time in the Supreme Court.

Cox was viewed with deep suspicion by the Nixon White House, even though he was picked by the President’s own Attorney General, Elliot Richardson, in the swirl of the Watergate scandal. The Nixon defenders saw Cox as a Kennedy Democrat who – like other political enemies -- would do anything within his power to bring down the embattled President.

Ironically, Cox was deeply respectful of the institutions of government and the President. He was loathe to think or act in political/partisan terms. Indeed, his first act as Watergate Special Prosecutor was to seek to shut down the televised hearings conducted by the Senate Watergate Committee chaired by the powerful Democrat from North Carolina, Senator Sam Ervin. Cox feared that the televised Watergate hearings might make it impossible to give President Nixon, White House aide John Dean, and other potential defendants a fair trial. When he made his case directly to Ervin, the Southern Democrat kicked Cox out of his office, calling him “arrogant.”

As the battle for the Watergate tapes turned into high drama, Attorney General Richardson pleaded with the White House to trust the Special Prosecutor. Richardson told President Nixon: “Archie Cox would just as soon cut off his right arm as do anything improper or partisan.” The President looked across his desk at the Attorney General and scowled.

The truth was, Archibald Cox was not eager to force a show-down with the President of the United States. He understood the principle of separation of powers, which cautioned against one branch of government intruding upon the province of another. He worried that demanding the Watergate tapes – private conversations that took place between President Nixon and his closest advisors in the inner sanctum of the Oval Office – might reveal the weakness of the rule of law in the United States. After all, the President’s private lawyer, Charles Alan Wright – one of the nation’s foremost Constitutional experts from the University of Texas – had just written Cox a stern letter warning him to back off, declaring: “The president could hardly allow others to rummage at will through his papers to see what they could find to be used to hurt him.” Who was Cox, a pesky Special Prosecutor who had never been elected by the people nor ­given any power under the Constitution, to be intruding on the President’s most private and sensitive records?

President Nixon and his team of advisors came very close to shutting down Cox’s operation and trumping the rule of law, even after two federal courts had ordered Nixon to turn over the Watergate tapes. The Nixon team concocted an elaborate and nefarious plan: Only one individual – Senator John Stennis of Mississippi – would be allowed to listen to the tapes and verify summaries of those tapes prepared by the White House for accuracy. Cox and his prosecutors would not be permitted to subpoena any further tapes or evidence. Senator Stennis, while an honorable man, was 71 years old, had trouble hearing, and had recently suffered gunshot wounds in a burglary attempt, causing him to be on heavy doses of medication. The White House planned to take Stennis to Camp David where Nixon loyalist, J. Fred Buzhardt, would “assist” Stennis in verifying the transcripts and in bringing the Watergate investigation to a dramatic halt. Just days before the President’s deadline to file an appeal to the Supreme Court in the Watergate tapes case, the White House abruptly announced that the “Stennis compromise” had been accepted by all parties. At this moment, the entire system of government in the United States teetered on a dangerous precipice.

When Archibald Cox took the long, lonely walk from his office on K Street to the National Press Club in Washington, to hold a press conference explaining to the American public why he could not in good conscience accept the Stennis Compromise – because it would violate his oath to the Senate to follow the Watergate evidence wherever it took him, even if it led the White House – he worried that he was “getting too big for my britches.”

Cox didn’t set out to defy the President of the United States. Yet Constitutional principles he cared deeply about, he told the hushed audience of reporters at the National Press Club, were at stake. If he allowed the President to shut down the Watergate investigation to suit his own self-interests, thumbing his nose at the rule of law, how could our nation hope to fight off tyranny when a future power-hungry leader declared that he, too, was above the law?

Fortunately, Cox’s absolute integrity on display that Saturday afternoon – October 20, 1973 – made a deep impression on the American people. When President Nixon that night ordered Attorney General Elliot Richardson to fire Cox, Richardson refused, resigning rather than carry out the President’s order. The next in command, Deputy Attorney General William Ruckelshaus, likewise resigned rather than do Nixon’s bidding. It was the third in command, Solicitor General Robert Bork, who finally carried out Nixon’s order to discharge Cox. Within hours of executing this Saturday Night Massacre, a firestorm of public protest erupted that led to the appointment of a new special prosecutor – Leon Jaworski – the subpoenaing of dozens of additional damning tapes, the drafting of impeachment resolutions against the President by both Democrats and Republicans in Congress, and the ultimate unravelling of the Nixon Presidency.

The events culminating in the Saturday Night Massacre, one of the most dramatic moments in American political history, impart a lesson that remains crucial for those who value our Constitutional system: It is only when public servants of great integrity – such as Archibald Cox, Elliot Richardson and William Ruckelshaus – stand up in times of crises and do the right thing, even though this may jeopardize their own personal career ambitions and interests, that our system is strong enough to withstand frontal assaults on the Constitution’s delicate balance of power.

These events ultimately proved that in the American system, no person, not even the President, is above the law – a point underscored when the United States Supreme Court handed down its historic decision in July of 1974 in U.S. v. Nixon – ordering President Nixon to turn over the full set of Watergate tapes, ultimately forcing him to resign in disgrace.

President Richard M. Nixon allowed his deep suspicion of others, and his belief that he could eradicate all threats to his presidency by exercising unbridled power, to cause him to misjudge many things. Perhaps his greatest misjudgment, however, was in thinking that he could overpower the will of the people themselves, when they – not Congress, not the Supreme Court, and certainly not one reckless President -- have the final say in our Constitutional system.

Ken Gormley is currently the President of Duquesne University. In 2013, he was the Dean of the Duquesne University School of Law when he wrote this article.