ALVIN FORD is under sentence of death for the 1974 killing of a Fort Lauderdale police officer. For 11 years he has been on death row, one of 225 Florida inmates now awaiting execution. From time to time the lights dim in the Florida State Prison as officials test the electric chair. A number of his fellow inmates have already been put to death, and twice Mr. Ford came within hours of execution, winning a postponement as the deadline drew near. Living under this kind of stress could drive a man to insanity, and that's exactly what his lawyers say has happened to Mr. Ford.

It is a common law principle, observed for many hundreds of years, that a person should not be executed if he cannot understand his impending death or the reason for it. All of the states that have a death penalty prohibit its imposition on a person who is insane. But the states have various ways of determining whether a prisoner is, in fact, insane. Some provide full hearings and judicial review, but in Florida the governor alone makes the decision. And Gov. Robert Graham, on the advice of three psychiatrists sent to examine Mr. Ford, has approved the execution.

This week, the Supreme Court agreed to hear Mr. Ford's appeal, which raises two questions: 1) Is there a federal constitutional right not to be executed while insane, and 2) if so, what procedures are required to satisfy it. The Florida appellant claims such a right under the Eighth Amendment and believes he is entitled to a full hearing on the question of his sanity.

For the last two years, according to his lawyers, Mr. Ford's condition has deteriorated markedly. He mutters incoherently and speaks in codes. He says he is the victim of a conspiracy involving CBS, the KKK and the CIA. Two psychiatrists hired by his attorneys say he is insane and should not be executed. Of the governor's three experts, one found that he was faking his symptoms. The others told the governor that he is psychotic, but "competent" to be executed since, presumably, he understands what is happening to him.

The record, in short, is confused and inconsistent, and a hearing with cross examination of the experts is needed. That would be true, however, even if the case were less muddled, for in every case of this sort a human life is at stake. The cost and inconvenience of a hearing -- already provided in many states -- is small price to pay to avoid the barbarity of executing an insane man.