Palm Beach Post pop columnist Leslie Gray Streeter explains the magic formula behind her favorite TV show of all time:

5 REASONS ‘L&O’ HAS LASTED

Like a Palm Beach socialite, it’s not afraid to get a little work done: Over the past 20 years, the show has had a staggering 26 regular cast members, with S. Epatha Merkerson, who showed up in Season 4, ranking as the veteran. Sometimes, people leave voluntarily (Dennis Farina, Benjamin Bratt ), and other times, they’re shown the door (Elisabeth Rohm ). But each time, they’re replaced, with usually a brief line the next season explaining their absence (“So, I know you don’t know me as well as Detective Blahblahblah”), and then life goes on. It probably doesn’t do a lot for individual actors’ feelings of specialness, but it does wonders to keep the show fresh.

Still, it doesn’t mess with the formula that made it a hit: Here’s what happens in pretty much every episode of Law & Order: Some hapless sap stumbles over a body. The cops come. They blame somebody. He or she didn’t do it. They find the right person and blame them. That person goes on trial. DA Jack McCoy or one of his minions gets all blustery and threatens to explode. The verdict is read. Something really dramatic happens. The end. You think this would get old. Surprisingly, it does not.

It’s not afraid to kill your favorite characters, if it makes a good story: In the very first season, we got to love and respect Detective Max Greevey (George Dzundza). We saw him form a loving, gruff partnership with partner Mike Logan (Chris Noth). We met his family. And then we see him murdered in his driveway. Producer Dick Wolf has employed this shocking way of delivering a pink slip a couple of times (ADA Claire Kincaid was killed by a drunken driver, and ADA Alexandra Borgia was killed by a gangster and stuffed in a car trunk), and it never stops being shocking.

Its casting looks like America: NBC threatened to cancel the show after Season 3 if Wolf didn’t add some women to the mix, which is why Lt. Anita Van Buren (Merkerson) and Claire Kincaid (Jill Hennessy ) showed up. Since then, there have been several women, older people, African-American and Latin cast members. We’re still waiting for Asian, gay and Middle Eastern actors and characters to join the party, but it’s done better than a lot of shows, for a really long time.

It’s not afraid to be tacky: I’ll be the first to admit that in 2009, Law & Order doesn’t attack as many deep issues of race, gender and sexual orientation as it did at the beginning, because it’s so busy ripping stuff from the headlines. (Celebrity adoptions? Check. Anna Nicole-esque pin-ups? Checkity check. A Britney/K-Fed situation? Oh, yeah.) Only one of those episodes was really excellent, but the tabloid factor, combined with the show’s brisk pace, made for some mighty entertaining TV.

I have resigned myself to the possibility that this might be Law & Order’s last hurrah, because Friday night usually equals death, and because Jay Leno is currently eating up all the 10 p.m. time slots, meaning that there will be less room for scripted dramas that perform less than excellently.
And I’m saddened but OK with it. I’m sure that Wolf will, if he has to, end things with a great crazy bang, with all the self-righteousness, indignation, grandstanding and quippery we’ve grown to love.

And if I get really lonely, there always are reruns on TNT. And I mean, always.

THE BEST & WORST OF LAW & ORDER’S TWO DECADES

Best detective partnership: Lennie Briscoe (Jerry Orbach) and Ed Green (Jesse L. Martin): Before veteran Lennie was paired with Green, a hot-headed former gambling addict, he’d become weary from the loss of his daughter and lost a little bit of his mojo. But Green’s enthusiasm for (ahem) boisterous interrogation tactics and dedication to the job not only re-lit a spark in the old guy but created a deep friendship whose loss (sob) finally made Green turn back to the bookie. Tragic.

Best cast lineup: Jerry Orbach , Jesse L. Martin , S. Epatha Merkerson , Sam Waterston , Angie Harmon , Steven Hill

Best ADA: Abby Carmichael (Angie Harmon): Abby’s range of emotion wasn’t generally very deep, stretching from mild annoyance to righteous glowering to full-out vengeful Texas fury. But of all the second chair prosecutors, she was the most sure of herself and her convictions. And those convictions, as she said in her very first episode, were usually ‘No deals for anybody. Hang ’em all!’ She scares us so.

Worst ADA: Alexandra Borgia (Annie Parisse ): Be careful what you wish for — I used to wish for the show to write out Elisabeth Rohm and her bland, self-righteous Serena Southerlyn character, but she at least had a backbone. Alexandra was meek like a wide-eyed prosecutorial fawn. That doesn’t mean she deserved to wind up dead in the trunk of a car, of course.

Worst detective: Nina Cassidy (Milena Govich ): I guess the departure of Dennis Farina’s Joe Fontana gave producers a chance to bring in some new blood. But Nina, dubbed Detective Beauty Queen because of the beauty parlor heist she’d thwarted before being promoted to detective, was a little too new. She put investigations in jeopardy with her hotheadedness, ran her mouth unnecessarily and never quite got on the good side of her boss, Lt. Van Buren (S. Epatha Merkerson). Or mine, for that matter.

Best detective: Lennie Briscoe, because he became the heart and soul of the show, and because his absence, in a show with a built-in revolving door, is the one felt the deepest. And those inappropriate zingers that he used to let fly after finding the body, before the opening credit? Priceless.

Best inappropriate Lennie Briscoe zinger over a dead body: (Investigating the murder of a delivery man killed by an exploding package) ‘When you absolutely, positively have to kill someone overnight.’

Best never-solved mystery: Just where Italian shoe and expensive car-loving detective Joe Fontana (Dennis Farina ) got all his money from. His colleagues wondered just how a cop afforded all that GQ booty, but Fontana — and the show — never explained, which made him all the more intriguing.

Best spinoff: Law & Order: Criminal Intent

Worst spinoff: Law & Order: Trial By Jury

Best surprise: How good Anthony Anderson , who made his name being the slobby guy in pretty much every 1990s and early 2000s movie with an all-black cast, turned out to be. As Detective Kevin Bernard (Season 19-), he’s shown a gravity and a sensitivity that he didn’t explore while stealing an ATM in Barbershop. Also, we never really noticed how handsome he is before now.

‘GUNSMOKE VS. ‘LAW & ORDER’!

As ‘Law & Order’ enters its 20th season, it ties with ‘Gunsmoke’ as the longest-running prime-time drama in television history. They’re both about laying down the law (and order) in a frontier town. The casts could even be interchangeable:

PRINCIPLED, TACITURN LAWMAN
Gunsmoke: Matt Dillon (James Arness)
Law & Order: Lennie Briscoe (Jerry Orbach)

CRUSTY SAGE
Gunsmoke: Doc Galen Adams (Milburn Stone)
Law & Order: DA Adam Schiff (Steven Hill)

HOT LOYAL SIDEKICK
Gunsmoke: Quint Asper (Burt Reynolds)
Law & Order: Mike Logan (Chris Noth)

GRUFF EXTERIOR, TENDER HEART
Gunsmoke: Miss Kitty (Amanda Blake)
Law & Order: Lt. Anita Van Buren (S. Epatha Merkerson)