It’s not often that while watching a congressional hearing on television a French expression pops into my mind. But the appearance of President Trump’s former personal lawyer and fixer, Michael Cohen, before a House committee last week sent me, as a veteran of Watergate, to the dictionary to look up “plus ça change, plus c’est la même chose” — “the more things change, the more they stay the same.”

Mr. Cohen’s testimony took me back to the summer of 1973, when I was moving to Washington to become NBC’s White House correspondent. Specifically, to the testimony of a former White House counsel, John Dean, and his description of President Richard Nixon’s knowledge of the Watergate affair. Mr. Dean, like Mr. Cohen, had once been a confidant of a vindictive president who turned on him.

The memory brought to mind the many parallels between the two presidents.

There are their top aides lost to scandal. For Mr. Nixon: H.R. Haldeman, John Ehrlichman, John Mitchell, Egil Krogh, Dwight Chapin, Jeb Stuart Magruder, Charles Colson and other lesser members of the team who were caught up in the Watergate scandal. For Mr. Trump: Michael Flynn, Tom Price, Scott Pruitt and Ryan Zinke, who were forced out in scandal — not to mention a long list, sure to grow yet longer, of people who have resigned in shame or out of disgust.

There are the odd bedfellow celebrity allies. Mr. Nixon was famously befriended by Elvis Presley, who wanted to help in the war on drugs. Mr. Trump welcomed the rapper Kanye West to the White House, where they talked about prison reform, running shoes and the power of Make America Great Again caps.