The first hearing of the House Judiciary Committee into the crimes of Donald Trump explored the analogy between Richard Nixon’s obstructions of justice in the Watergate affair and Trump’s obstructions in Special Counsel Robert Mueller’s probe of Russian interference in the 2016 election that was intended to assist his candidacy. The first witness, John Dean, who had been Nixon’s White House legal counsel and exposed his “cancer on the presidency,” testified that Trump’s crimes were comparable to Nixon’s. “It’s quite striking and startling to me that history is repeating itself—and with a vengeance,” he said. He pointed the committee to the Mueller Report as “a road map.”

But one major dissimilarity between the Nixon and Trump cases is as revealing and central as the “striking” parallel between their abuse of power—and makes the case against Trump all the more secure. The contrasting sequences in the disclosure of damaging information shows that the progress in establishing Trump’s crimes is more concrete, unambiguous and undeniable than Nixon’s were until the climax of his scandal. That difference is not a merely intriguing footnote, but fundamental to understanding how the current investigation of Trump would most probably unfold. In Nixon’s case, the incriminating piece of evidence, which became known as the “Smoking Gun” tape, was not exposed until the very end; in Trump’s case, however, the incriminating evidence in the form of many smoking guns lie in plain sight on the table like Poe’s supposedly hidden purloined letter.

The Senate Watergate Committee began its hearings on May 17, 1973. In his testimony that June, John Dean raised his suspicion that Nixon was taping his conversations. A month later, in July, Alexander Butterfield, the deputy chief of staff, who had installed the taping system, testified to its existence. Special Prosecutor Archibald Cox promptly filed subpoenas for the tapes. Nixon invoked executive privilege. District Court Judge John Sirica ruled that Nixon must turn over the tapes. Nixon stonewalled. Negotiations went nowhere. On October 20, in the “Saturday Night Massacre,” Nixon fired Cox, and Attorney General Elliot Richardson and Deputy Attorney General William Ruckelshaus, who refused to do his bidding. The court appointed Leon Jaworski as Special Prosecutor, and he drew up a confidential “roadmap” for his investigation that was not made public until 2018. Despite the firestorm over Cox’s dismissal, it took until February 6, 1974 for the House to authorize the Judiciary Committee to initiate an impeachment inquiry, which hired a staff to begin the formal process of gathering evidence. On April 11, the Judiciary Committee subpoenaed the tapes. Nixon handed over a batch of edited transcripts. The committee opened public hearings on May 9. On July 24, the Supreme Court ruled unanimously in United States v. Nixon, a case filed by Jaworski, that Nixon must turn over the tapes. Three days later, over the course of three days, the Judiciary Committee passed three articles of impeachment. On August 5, the “Smoking Gun” tape proving Nixon’s obstruction of justice was revealed. He resigned on August 9.