The execution of Thomas Knight last week is a textbook case for why Florida’s dysfunctional death penalty should be scrapped.

Here was a man whose guilt was never in doubt, whose crimes were cold-blooded, whose attitude remained remorseless and often defiant — yet the system took nearly 40 years to close the book.

In South Florida, Knight will be remembered for abducting and killing a Bay Harbor Islands couple, Sydney and Lillian Gans, in 1974. After a frantic manhunt, he was found hiding in the mud with the rifle used in the crime, and $50,000 cash that he’d forced Gans to withdraw from a bank.

Ironically, Knight wasn’t executed for those murders. In 1980 he fatally stabbed prison guard Richard Burke with a sharpened spoon, and it was that homicide that finally delivered him to the death chamber for a lethal injection.

His case had dragged on so long that last year a federal appeals court lamented: “To learn about the gridlock and inefficiency of death penalty litigation, look no further than this appeal.”

The daughter of Sydney and Lillian Gans didn’t attend Knight’s execution because of poor health. At 73, she is now older than her parents were when they were slain.

For decades, the dogged maneuvering and serial delays in capital cases have frustrated prosecutors and police, and brought more misery to the victims’ relatives. There is no workable solution except to repeal the death penalty and replace it with mandatory life sentences.

Because appealing a capital case involves both state and federal courts, it can’t simply be expedited by legislation. And because people do get wrongly convicted — as organizations such as the Innocence Project have demonstrated — judges must be cautious and thorough.

Convicted of a rape and murder in 1986, Florida Death Row inmate Frankie Lee Smith was exonerated by DNA evidence in December 2000. It was too late. Smith had died of cancer 11 months earlier in prison.

For obvious reasons, defense lawyers in death cases strategize to stall, stall and then stall some more. Their job is to keep their clients alive as long as possible.

Florida fought 10 years to execute the notorious Ted Bundy, at a cost to taxpayers of about $5 million. There’s no calculation as to how much was spent litigating the case of Thomas Knight, who received his first death sentence in 1976, but you can be certain it was a fortune.

Set aside for a moment the moral and religious objections to capital punishment, and the questions about its disproportionate application to minorities. Consider the statute strictly as an expensive, endless drain of legal resources.

Since the death penalty was reinstated in 1976, Florida has averaged slightly more than two executions a year while adding about 12 new residents annually to Death Row. You can do the dismal math in your head.

Today 396 men and five women live on Florida’s Death Row, and most (if not all) have attorneys working on appeals. The pace could never be described as swift.

Knight was no anomaly; many capital cases have been slogging along since the mid-1970s.

One of the most infamous is that of James Rose, a house painter convicted of snatching his ex-girlfriend’s 8-year-old daughter from a Hollywood bowling alley, then killing the girl and dumping her nude body in a canal.

The shocking crime happened in October 1976, when Rose was 30 years old. Last month he turned 68, and he continues to file appeals.

Multiply his paperwork by 400 and that’s what faces the state. On both sides of each marathon case, taxpayers usually get stuck with the legal bills. That won’t change, either, unless somebody rips up the Constitution.

However richly a killer like Thomas Knight deserved to die for his crimes, the exorbitant cost of executing him is impossible to justify at a time when the courts are understaffed, underfunded and swamped.

It would be vastly more economical and efficient to give up on capital punishment and impose mandatory life sentences, as 18 states already do.

At this point a death sentence is practically a de facto life sentence, anyway, given the longevity of the appeals process. By the time it’s over, families of the victims are as wrung out as they are relieved.

The day before Knight was put to death, another Death Row veteran named Robert Patten departed without fanfare. Many won’t remember who he was, but back in 1981 he shot dead a young Miami police officer named Nathaniel Broom.

Patten was first sentenced to die in 1985, appealed, was resentenced to die in 1989, and of course continued to appeal.

Twenty-five long years later, he wasn’t even executed by the state. Prison officials said he died of natural causes, which isn’t uncommon on Death Row due to the aging inmate population.

It’s time for Florida to get out of the costly execution business, and let cancer and clogged arteries do what the justice system can’t.

(Carl Hiaasen is a columnist for The Miami Herald. Readers may write to him at: 1 Herald Plaza, Miami, Fla., 33132.)

Photo: Casey Konstantín via Flickr