Question: Who played the part of the assistant district attorney on Law & Order before Sam Waterston?
Televisionary: Well, technically there's more than one answer to that. Richard Brooks portrayed ADA Paul Robinette from the time the NBC series debuted until his departure in 1993. However, I assume you mean Michael Moriarty, who left the show after a very public tiff with L&O head man Dick Wolf over the actor's outspoken criticism of then Attorney General Janet Reno and her effort to curb TV violence.
Wolf and NBC West Coast President Don Ohlmeyer took Moriarty along to a meeting with Reno, but they probably could've chosen someone a little better versed in diplomacy. Reno, Moriarty said in a letter urging President Bill Clinton to fire her, is a "mindless attack dog in the spirit of Joe McCarthy." And lest she miss out on that particular opinion, he fired off a one-sentence note directly to her: "The next time you call me to a meeting where only one side gets to ask the questions, send a subpoena."
The result? Hello, ADA Jack McCoy (Waterston).