James Squires was editor of the Chicago Tribune from 1981 to 1989.

President Trump’s angry railing against leaks calls to mind my experience as a newly hired national political correspondent in the Washington bureau of the Chicago Tribune in 1972. The Tribune was a powerful Republican voice of Midwest conservatism and a staunch Nixon backer, and I was the paper’s lone Watergate reporter, trailing in the wake of The Post’s Bob Woodward and Carl Bernstein.

Whenever cornered, President Richard Nixon invariably excused the existence of the burglary team that The Post had traced to the White House by contending that these “plumbers” were not out to wiretap the Democratic National Committee but were on a mission to investigate leaks concerning a matter of national security so grave and highly classified it could not even be discussed in public.

If there was one big story that The Post was yet to break, it was the nature of this mysterious national security matter. So in partnership with another lone-wolf Watergate reporter, Dan Thomasson, Washington bureau chief of Scripps Howard, I began to chase it. We were two among many.

Just before Christmas 1973, I received a leak.

In secret testimony before the Senate Watergate Committee, White House Counsel John Dean had submitted a written document so explosive it had been shared with only the committee’s chairman, Sam Ervin (D-N.C.), and vice chairman, Howard Baker (R-Tenn.), before being locked in the safe of the Atomic Energy Committee.

According to my anonymous source, the document not only showed that Nixon’s national security claim was bogus but also included a list of illegal wiretaps and “black bag burglaries” committed by the FBI. For days, the anonymous person resisted my pleas for details.

John Dean, President Richard Nixon’s former White House counsel, is sworn in by Senate Watergate Committee Chairman Sam Ervin before testifying on Capitol Hill on June 25, 1973. (Associated Press)

Eventually, in the interest of some agenda about which I could only surmise, I was instructed to come to a Capitol Hill office building just before it would close for the evening and go to a specific unmarked door behind which was a room empty but for a desk with an unlocked drawer. Inside was a copy of the Dean document. I was instructed to leave no fingerprints and had an hour to take notes. I had to promise I would go to jail rather than ever say how I got the story.

There was no security classification on the document, nor should there have been. Nixon’s highly classified excuse turned out to be an insignificant but embarrassing episode in which a lowly Navy yeoman, assigned as an aide to national security adviser Henry Kissinger, had been copying the contents of Kissinger’s briefcase and passing them to his superior, a rear admiral who served as deputy to Thomas Moorer, then chairman of the Joint Chiefs of Staff. One of the pilfered documents, suggesting that Kissinger favored a tilt in U.S. foreign policy away from longtime ally India toward its rival Pakistan, had ended up in a column by Jack Anderson. One of Nixon’s plumbers had suggested that Anderson become the victim of an auto accident — or just be assassinated.

The editor of the Tribune at the time was Clayton Kirkpatrick, a cautious and reliable custodian of the kind of power that editors of major newspapers used to wield. At first he seemed saddened that Nixon’s excuse for employing burglars was just another lie and by the illegal FBI activities Dean detailed. But then Gen. Alexander Haig, serving as White House chief of staff, telephoned Mr. Kirkpatrick — he was always “Mr.” to me — to warn that publication would “not do our country any good.” Not only would the Tribune endanger national security, Haig argued, the world would lose respect for America’s leadership.

Gen. Alexander Haig, right, with President Richard Nixon in May 1973. (UPI)

My story had been scheduled to run on Sunday, Jan 6. But then it didn’t. Kirkpatrick blocked it. Thomasson was set to publish his version in the Monday afternoon Washington Star but out of deference to our casual partnership held that up as well.

Kirkpatrick, ever the reasonable and courteous gentleman, and I, not so much, went round and round for a week, until, as the following Sunday approached, I offered to simply hand my notes over to Thomasson — or take them over to The Post, which might result in the truth coming out and a possible job interview. Kirkpatrick asked me to wait. Meanwhile, a friend with knowledge of the National Security Council informed me that “the White House is very angry and afraid” and added the disturbing news that if Haig’s call did not kill the story, “other means” were being considered — whatever that meant.

A few hours later, Kirkpatrick called me back and quietly announced: “I just talked to Ben Bradlee at The Post and told him about your story and the call from General Haig.” Before I could explode, Kirkpatrick added, “Ben said, ‘Clayton, if I had that story, I would run it in the morning.’ So we are going with it.”

Years later, on an editors’ junket to Russia, Bradlee and I reprised the incident.

“I bet you thought Clayton had given your story away,” Bradlee said.

“We both knew that since The Post was taking so much heat, that story would have more impact coming from the Tribune. When the press has an enemy in White House and we are all on the same side, we are at our best.” Then with a flash of his inimitable swashbuckling style, Ben added, “Besides, we were doing pretty damn well on our own.”

My piece ran on Sunday, Jan. 13, and Thomasson’s the following day. Back then, when newspapers and the three networks were the main source of news, it was a bombshell of sorts.

Leaks rebuking lies are critical to the balance and separation of powers written in the Constitution. They often come from the highest-level sources and for much less uplifting reasons than you might guess. One of mine came from President Lyndon B. Johnson himself, concerning a Tennessee woman arrested by East Germans and charged with spying. It was 20 years before I learned Johnson had done so in a fit of pique over a Post editorial criticizing his foreign policy.

Similarly, the late James Angleton, America’s most famous counterspy, slipped me the history of a ridiculously expensive recovery vessel called the Glomar Explorer and a few years later laughed that it was an effort to upstage a New York Times investigative reporter he knew was chasing the story.

Some reporters have had their careers ruined by leaks. Mine benefited. Largely due to the leak of the Dean document, the most significant leak of all my time in Washington as a reporter followed from a different source. One night in late April 1974 — three days before the printed transcripts of the damning Watergate tapes were to be released in response to a House Judiciary Committee subpoena — an anonymous White House source, whose motives remain a secret from me even today, delivered several purloined copies to the Tribune Washington bureau, as promised. A trio of editors aboard a Tribune jet frantically read them on the way to Chicago.

President Nixon announces the release of Watergate transcripts on April 29, 1974. (Associated Press)

The next day was spent assessing with Kirkpatrick the likely consequences of the pending publication, a blockbuster scoop that ultimately branded Nixon as the biggest proven liar ever to occupy the Oval Office. It was followed by a three-part editorial calling on the president to resign, which he did later in the year.

Fourteen years later, Nixon came to Washington in response to my invitation to speak to the American Society of Newspaper Editors. Upon his arrival at the hotel, Nixon greeted me like a long-lost relative, pulled me aside and told me that he believed the Tribune’s demand that he resign is what stripped him of his remaining congressional support and ultimately convinced him to quit.

Every president hates leaks; few have been as undone by this hatred as Nixon. As a confluence of leaks, lies and White House efforts to muzzle the press, the parallels between Nixon and Trump cannot be overstated. So as Trump fumes, I sit here in Mitch McConnell country, rooting for the “leakers” and the reporters brave enough to take a risk for the truth.