This piece was originally published on Just Security, an online forum for analysis of U.S. national security law and policy.

The Trump team has long engaged in a concerted effort to lie about campaign contacts with Russians during the 2016 election. Of this all reasonable observers know. Even some Trump supporters bemoan such a strategy ever took place, but it happened. The term for it is a cover-up.

Senior Trump campaign officials did not just lie to the media and the public. They also lied to federal authorities or risked doing so. At least they were “chancing a very high risk for a perjury situation,” as White House counsel John Dean put it to President Richard Nixon in plotting the Watergate cover-up. The list of associates who have either been proven to have taken this path—or seem to have—includes, in chronological order:

1. Jeff Sessions, who told Congress he had no contacts with Russians about the election (Jan. 10 and 17, 2017)

2. Jared Kushner, who omitted key meetings with Russians on his security clearance forms (Jan. 18, 2017)

3. Michael Flynn, who lied to FBI investigators about whether he discussed U.S. sanctions for election interference with the Russian ambassador (Jan. 24, 2017)

4. George Papadopoulos, who lied to FBI investigators about his contacts with Russian agents (Jan. 27, 2017)

5. K. T. McFarland, who told Congress she was not aware of Flynn’s contacts with the Russian ambassador (sometime in July)

6. Donald Trump Jr., who told Congress that he did not inform his father of the Trump Tower meeting with Russians and senior campaign officials (Sept. 7)

That list is just based on current public information, and may grow. (I’m also excluding from the list Paul Manafort and Rick Gates, who have been indicted for lying to federal authorities about their connections with Kremlin-linked Ukrainian parties.)

If you closely examine the record, the puzzle is whether the decision of so many of Trump campaign officials to chance a very high risk of perjury in covering up Russian contacts involved a tacit or explicit understanding on their parts to do so, and encouragement by the others—potentially including encouragement by the president himself.

In a piece in the New York Times on Thursday, I put together the pieces of the puzzle, based on what we can infer from the circumstances and conduct of the relevant actors.

Some points here to accompany that analysis:

First, it is not just a crime to lie to federal authorities, but also a crime to encourage others to do so. The technical term is “suborning perjury.” If such actions involved a conspiracy, it would likely strengthen prosecutors’ tactical advantages.

Second, if the president himself was involved in encouraging others to lie, that would be a clear case of obstruction of justice. Even those who have expressed a maximalist and mistaken view—that a president, as chief executive, cannot obstruct justice in closing down an investigation or removing an FBI director—acknowledge that if a president encouraged others to commit perjury that would be a crime. A proponent of the maximalist view, Alan Dershowitz, for example, has accepted that “if a president’s actions … are unlawful — as President Nixon’s clearly were when he told subordinates to lie to the FBI and pay hush money — good intentions…would not be a defense.”

Third, the history of Watergate has a lesson about the gravity of such actions, and how awareness of them by conservative federal prosecutors could set other pieces in motion. Watergate special prosecutor Leon Jaworski, from Houston was brought in to replace Cambridge, Massachusetts’ Archibald Cox on the theory that Jaworski would be much more favorable to the White House. But a personal turning point for Jaworski was when his staff asked him to listen to a tape of the president encouraging associates to commit perjury.

On the recording, Nixon could be heard telling Dean and Chief of Staff H.R. Haldeman, “Just be damned sure you say ‘I don’t remember. I can’t recall, I can’t give any honest—an answer to that that I can recall.’ But that’s it.”

An insider account written in 1977—Jim Doyle’s book, Not Above the Law—recounts Jaworksi’s reaction:

Jaworski reddened. “Can you imagine that?” he said. “The President of the United States sitting in his office telling his staff how to commit perjury.” Jaworski spoke of this exchange many times over the next months. It was something he could not accept.

A BBC documentary (3:23:49-3:27:28) powerfully captures this momentous turn in the Watergate prosecution.

At this point in our own time, it is naturally far too soon to draw any hard conclusions about what specific role President Trump might have played. For the empirical case of what pieces of the puzzle we do have about the Trump inner circle, please read my piece in the Times, and decide for yourself whether there was likely any conspiring to mislead federal authorities.

More from Just Security:

Collective Self-Defense and the “Bloody Nose Strategy”: Does It Take Two to Tango?

Three Insights Into Attempted Firing of Mueller and Obstruction of Justice