Geoff Shepard was associate director of the White House Domestic Council and served on President Richard Nixon’s Watergate defense team. He is the author of The Secret Plot to Make Ted Kennedy President and is writing a book on prosecutorial and judicial misconduct in the Watergate trials.

Watergate remains the greatest political scandal in modern American history. It culminated not only in President Nixon’s announcement of his resignation, 39 years ago Thursday, but in the conviction and imprisonment of his three most senior aides. Attorney General John Mitchell, White House Chief of Staff H.R. Haldeman, and Assistant to the President for Domestic Affairs John Ehrlichman were found guilty of conspiracy, obstruction of justice, and perjury in the three-month Watergate cover-up trial, which ended on January 1, 1975.

I saw it all unfold. I was a young lawyer working on the White House staff and assisting in Nixon’s defense efforts. It is true that we failed spectacularly. Of course, I’m disappointed we weren’t more successful. But whether the defendants were innocent or guilty, I’ve always worried on a more basic level that the heightened emotions of the times denied them the due process of law envisioned by our Constitution.

As a result of some recent discoveries I made while researching a book on the Watergate trials, my concern has been vindicated. It turns out that the notion that “no man is above the law” somehow didn’t apply to judges or prosecutors involved in the cover-up trial. Documents I have uncovered indicate that the efforts to punish the wrongdoings of Watergate led to further wrongdoing by the very officials given the task of bringing the Watergate defendants to justice....