The obvious is being repeated all over the media: FBI Director Comey’s abrupt firing by President Trump can only be compared in its gravity to President Nixon’s firing of Special Prosecutor Archibald Cox on Saturday, October 20, 1973 — the so-called “Saturday Night Massacre.”

Thus, it is important to know more about this historical reference to understand its potential significance to current events.

So consider this a backgrounder on the SNM.

The saga starts with President Nixon’s firing of his top advisers and his White House Counsel in April 1973. Nixon terminated the employment of his chief of staff, H. R. Haldeman, his top domestic adviser, John Ehrlichman, and his White House Counsel, John W. Dean. Dean had broken with the White House and was cooperating with prosecutors and the Senate investigators for the Watergate Select Committee.

Nixon also let go his attorney general, Richard Kleindienst.

The reason for these terminations was obvious — Nixon needed to do something to staunch the bleeding from the growing Watergate scandal and he threw Dean in particular under the bus by suggesting that he knew nothing about the Watergate cover-up until Dean had told him about it on March 21, 1973, when Dean warned Nixon there was a “cancer growing on the presidency.”

But there was a built-in problem: When Nixon relieved his attorney general, he had to replace him with someone new, and that candidate would require Senate approval.

Nixon nominated Elliot Richardson, a man who had served in his cabinet and was a trusted figure on Capitol Hill.

But Richardson had gone to Harvard Law School — Nixon hated the eastern establishment and elites, so this nomination should have caused Nixon to pause.

The Senate insisted that Richardson agree to support a Special Prosecutor to look into Watergate on behalf of a grand jury that had been investigating the break-in.

Richardson agreed and then appointed his esteemed law professor from Harvard, Archibald Cox.

Cox assembled a staff of eager and smart young lawyers, including Richard Ben-Venista and Jill Volner, and they all went to work.

Then a revelation: Nixon had a taping system.

On July 16, 1973, Alexander Butterfield testified (after John Dean’s stunning testimony in June 1973) that indeed Nixon had installed a taping system — one that was voice-activated, so it recorded all the conversations the president had in the Oval Office, the Executive Office Building and Camp David.

Cox moved quickly to subpoena certain tapes, mostly to corroborate what Dean had testified to in his appearance before Sam Ervin and the Watergate Select Committee.

Nixon fought the subpoena. There was precedent for a president ignoring a subpoena from the judicial branch—a co-equal branch of the government. In addition, Nixon asserted Executive Privilege.

The case went to the courts and they ruled in favor of Cox and the grand jury, but suggested that the Special Prosecutor and the White House work out a deal.

Nixon, knowing of all the damning conversations on the tapes, proposed a ruse. He offered to make transcripts of the tapes and then he would allow a senior Senator listen to the tapes to verify the accuracy of the transcripts.

That Senator was John C. Stennis of Mississippi. A problem: Stennis had been mugged and shot nine months earlier in Washington, and to make matters worse, he was extremely hard of hearing.

Cox would have nothing to do with the “Stennis Compromise.” The evidence collected in this manner could not be used in court and Cox frankly didn’t trust Nixon to prepare accurate transcripts of the tapes.

The showdown came to a head on October 20, 1973, when Nixon instructed his attorney general, Elliot Richardson, to fire Cox. Richardson refused and resigned. So did his deputy, William Ruckelshaus. Finally, the solicitor general, Robert Bork, complied with Nixon’s order (this act would haunt Bork when President Reagan nominated him to be a Supreme Court justice―-Bork was rejected by the Senate).

The reaction to the firing of Cox was swift and strong. Calls for impeachment in the Congress were legion. The end was now all but guaranteed for Nixon.

What everyone knew—as might be the case today with Trump—is that Nixon was acting in a desperate manner to stop an investigation that he knew would show his guilt.

The fact that Comey was circling in on the Russian election-tampering scandal and possible collaboration with the Trump campaign is a fairly precise analogue to Nixon firing Archibald Cox.

It is just too obvious that there is an intention to block or at least slow down an investigation that is going badly for the Administration.

We know from Nixon’s tapes that he was deeply involved in the cover-up. The tapes proved it. Removing Cox was a ham-handed way for him to try to stop it and all it did was breathe fire into the impeachment effort—which eventually resulted in Nixon’s resignation once the tapes were ordered to be produced by the Supreme Court of the United States.

James Robenalt is the author of January 1973, Watergate, Roe v Wade, Vietnam, and the Month That Changed America Forever. www.january1973.com. He lectures nationally with John W. Dean on Watergate and legal ethics. www.watergatecle.com.