After 12 years with Law & Order, Orbach announced in March 2004 that he would leave the show at the end of season 14 for the spin-off Law & Order: Trial by Jury. Lennie Briscoe was disbarred when he retired from the NYPD and later accepted a position as an investigator for the DA office. He was replaced in the 27th District by Detective Joe Fontana, played by Dennis Farina. At the time, Orbach refused to give a reason for his departure, but it was eventually revealed that he had battled prostate cancer (for over 10 years) and that his role in Trial by Jury was designed to be less painful for him than his role in the original series. However, Orbach died of cancer on December 28, 2004 and was only featured in the first two episodes of Trial by Jury. (His character was later written off and died off-screen, although in the original series this wasn`t written off until the 18th century. The season episode “Burn Card” was revealed.) On May 14, 2010, NBC officially dropped Law & Order, instead, Law & Order: Los Angeles opted for a first season and Law & Order: Special Victims Unit for a twelfth season.  Creator Dick Wolf continued to lobby the show`s producer, NBC Universal, to strike a deal with TNT, which held the rights to syndicate the series, for a twenty-first season if an acceptable royalty could be negotiated. Talks between the two began after Upfronts.  However, TNT stated in a statement that it was not interested in recording the show for a new season.  This season — which, by the way, was the highest-rated of the series — had a strong cop combination with Orbach, Martin, and Merkerson, but ended up in last place mainly due to the DA side of the equation.
Wiest never seemed quite comfortable in the L&O verse, and Rohm`s introduction was a bit shaky. On the prosecution side, Michael Moriarty was Dick Wolf`s choice to play Assistant District Attorney Benjamin “Ben” Stone. However, the network favored James Naughton, but in the end, Wolf`s choice prevailed, and Moriarty got the role. As his ADA, Richard Brooks and Eriq La Salle were considered for the role of Paul Robinette. The network favored La Salle, but again the choice of producers prevailed and Brooks got the role. As a boss, Roy Thinnes was appointed District Attorney Alfred Wentworth. Wolf pitched the idea to Universal Television`s president at the time, Kerry McCluggage, who pointed out the resemblance to a 1963 series called Arrest and Trial, which ran for one season. Both watched the pilot of this series, in which a police officer (Ben Gazzara) arrested a man for armed robbery in the first half and the defense attorney, played by Chuck Connors, eliminated the author in the second half as the bad guy; That was the formula of the show every week. Bratt left the show at the end of Season 9, stating that it was an amicable departure and that he expected to return for guest appearances at some point. (He eventually returned for the Season 20 episode “Fed.”) Detective Curtis was disbarred for leaving the troupe to care for his wife, who was suffering from multiple sclerosis, in her final days.  He was replaced by Jesse L. Martin as Detective Ed Green, who was designed more as a loose cannon in the guise of Logan of Noth than Curtis of Bratt.  (Briscoe was described as a recovering alcoholic, as Cragen had been; Green has been described as a recovering problem gambler.) In 2000, Steven Hill announced that he would leave the series after season 10.
Hill, who was the last remaining member of the original cast, said his departure had been friendly with the producers. He was replaced by Dianne Wiest as acting district attorney Nora Lewin, and Adam Schiff was struck off screen to work with Jewish charities and human rights organizations in Europe. Orbach`s Lennie Briscoe joined Law & Order for nine episodes of the third season, with Sorvino — who asked to leave in part because of the bloody schedule of an hour-long drama — being written after Cerreta was shot dead on duty. Orbach`s sardonic humor became a feature of the show, and he quickly became a fan favorite. Hennessy decided not to renew her three-year contract at the end of Season 6 to focus on other projects, and Claire Kincaid was disbarred after her death in a drunken car accident. She was replaced by Carey Lowell as Assistant Attorney Jamie Ross. Lowell stayed with the show until the end of season 8, when she left to spend more time with her daughter. (Jamie Ross was struck off for similar reasons for leaving the D.A. office.) Lowell (who later returned for a few guest appearances) was replaced by Angie Harmon as Assistant District Attorney Abigail “Abbie” Carmichael, who was designed to be much stronger and more outspoken than any of her predecessors. Harmon auditioned for the role with 85 other women, including Vanessa Williams, and was selected after Wolf heard her Texas accent. Law & Order also became famous for its turnover: 25 different actors played the six regular roles in the series, and no combination lasted more than 2 and a half seasons together. The series has had a changing cast over the years. The longest-serving main cast included Steven Hill as District Attorney Adam Schiff (seasons 1–10), Jerry Orbach as Detective Lennie Briscoe (seasons 3–14), S.
Epatha Merkerson as Lt. Anita Van Buren (seasons 4–20), Sam Waterston as Assistant District Attorney Jack McCoy (seasons 5–21; later District Attorney) and Jesse L. Martin as Detective Ed Green (seasons 10-18). Often, the plot of the first part of an episode resembles a recognizable aspect of a real case. In early seasons, details of these cases often closely followed true stories, such as the episode “Subterranean Homeboy Blues” from the first season, in which a woman shot two attempted assaults, alongside the case of Bernhard Goetz. Another episode of season 1, “Out of the Half-Light,” focused on a racist rape case that mimicked the Tawana Brawley case. This “ripped from the headlines” style is reflected in the opening credits, which evolve from halftone newspapers to high-resolution photos. Another episode of the first season, “Poison Ivy,” was based on the case of Edmund Perry, in which an NYPD official shot and killed a black student who committed a crime in front of the officer when he returned to town after graduating from an Ivy League kindergarten. Later seasons would draw on real cases, but deviate further from the facts.
Often this was done by increasing the seriousness of the crime in question, usually by adding murder. As a result, the plot would tend to deviate considerably from the actual events that might have inspired the episode.  Ads for episodes with similar real-life parallels regularly use the phrase “ripped from the headlines,” although a textual warning in the actual episode emphasizes that the story and characters are fictional.