Judge Howard S. Chasanow, renowned as a story-teller in the Prince George's County courthouse, has been telling a new one lately. He calls it, "the comma that saved a life."

It tells of a man sentenced to death who was en route to the gas chamber when a telegram from the Governor arrived saying, "Pardon, impossible to execute."

Reprieved, the man returned to his cell. It was only after the death penalty had been repealed that the warden learned that the telegram should have read: "Pardon impossible to execute. The accidental comma had saved the man's life.

The story is an appropriate one for Chasanow to be telling these days. Today he will become the first Maryland judge in five years to decide whether to sentence a man to death. What's more, the absence of a comma will play a crucial role in what Chasanow says will be the most difficult decision of his life.

That decision involves William Joseph Parker, the 28-year-old transient Prince George's County fireman convicted last month of felony murder in the death of 13-year-old Elizabeth C. Archard. The case was the first to be tried under the Maryland death penalty statute that went into effect last July.

But several attorneys now contend that the portion of the law that applies to Parker is made ambiguous by the absence of a comma. According to the statute, the death sentence can be imposed on an individual who commits murder while also committing, " . . . rape or a sexual offense in the first degree."

The lack of a comma after the word "rape" makes it unclear whether the term "first degree" applies to the crime of rape. If it does, Parker cannot receive the death penalty. But if it does not, Parker, convicted of murder and second-degree rape, could go to the gas chamber.

First-degree rape is the legal term for forcible rape, during which the victim is threatened with a weapon or is seriously injured. Second-degree rape is the nonviolent rape of a girl under 14 by a man at least five years her senior.

Today it will be up to Chasanow to resolve that ambiguity. If he finds the grammar leaves Parker eligible to face death, he then must answer a more difficult question: does he deserve it?

"I've been in each seat on this issue in the past," Chasanow said recently.

"I prosecuted a case where the death penalty was asked for, I've defended a man who faced death and now this. This is far the worst position to be in. I try not to think about it but it's hard to avoid it, I can't help but think about it."

After his arrest last summer, Parker admitted to the police that he picked Archard up about a mile from her home, drove her to a wooded area of Bowie and had sex with her. Then, he said, he blacked out. When he came to he was standing over Archard with a gun. The girl had been shot in the neck and chest a total of five times.

"There is no questioning that this was a heinous crime," defense attorney Fred Warren Bennett said recently. "But I think the judge will make a fair and impartial decision based on the law.

"There are a lot of judges on the circuit who I think would react simply to the idea of shooting a teen-ager five times and just give the death sentence based on that. Chas isn't like that. He's a thoughtful and compassionate man. That's why I opted to have him deliver the sentence instead of the jury."

Bennett's contention that Chasanow would be very reluctant to give Parker the death penalty was echoed during discussions with several other county judges.

"Chas doesn't have it in him to sentence a man to death," said one judge. "He can always see a good side to people and find a reason why they should be kept around or given anothter chance. I'm not like that. If it were me, the guy would get the death sentence. I think he deserves it."

Chasanow will not discuss his feelings on the death penalty or on this case. But he says his own emotions will play no part in his decision.

"My attitude towards the death penalty or towards this case is irrelevant," he said. "The legislature has laid down a clear set of guidelines. If I decide that under those guidelines a death sentence is warranted, that will be the sentence.

"I'm going to look at this as a legal decision and that's all." In order to ensure that his is not influenced by outside forces, Chasanow ordered his secretary to withold any mail on the Parker case from him until after the sentencing.

Try though he might, Chasanow cannot avoid the question. Other judges have approached him to give their opinion - most favor the death sentence. At a recent judicial conference Chasanow found himself surrounded by judges from all over the state, each with a very pronounced opinion.

No matter where Chasanow has gone the past few weeks, even usually private haunts, he found the sentencing is on everyone's mind.

Recently when Chasanow walked into the local Upper Marlboro hangout, a friend kidded about a misdemeanor sentencing that morning. "Did you give him death, Chas?" the judge was asked.

Chasanow smiled grimly and shook his head. "I just stopped thinking about that for 30 seconds and you had to bring it up," he said, his characteristic smile noticeably absent as he walked away.

Although it is obvious that he is feeling a great deal of pressure, public attention is nothing new to Chasanow.

Born in Greenbelt 42 years ago he is the son of Abraham Chasanow, the subject of one of the highly publicized controversies of the McCarthy era. In 1953, the Navy fired Abraham Chasanow from his civilian job, alleging that he had "Communist learnings."

A one-year legal battle followed and in 1954 Chasanow was reinstated with a public apology from the Navy, the first in the Navy's history. Once vindicated, Chasanow promptly quit his job and went into private practice as an attorney.

"That was an extremely traumatic time for me," said Chasanow, who was 17 at the time. "When my dad was vindicated the way he was it was very important to all of us."

His interest in the law was piqued by his father's experience. With his father's encouragement, he went to law school at the University of Maryland and later received a Master's of Law degree from Harvard.

He worked as a prosecutor in the state's attorney's office during the 1960s before joining his father in private practice in Prince George's. Concentrating on criminal law, he was named to a seat on the county's district court in 1972 and at the end of 1976 was named to a circuit court judgeship.

Chasanow hardly fits the stereotyped image of a judge. He stands five feet, five inches tall, has a ready smile, speaks softly from the bench and rarely looks sternly or threateningly at a defendant.

Attorneys who have argued before him say that what Chasanow lacks in hight or forbidding looks, he more than makes up for with his encyclopedic knowledge of the law.

During the Parker trial, defense attorney Bennett began citing an obscure 1885 California case to Chasanow as an example for a point he was trying to make. Before he could finish Chasanow interrupted, recited a portion of the ruling to Bennett and noted that he did not think the case fit Bennett's motion.

It is that kind of memory and knowledge that give Chasanow the label of "scholar," among fellow judges. It is his reputation for compassion which has given him the label "liberal."

"I don't like labels at all," Chasanow said. "Look, there are some crimes where I'm the toughest judge on this circuit. Second offenders on [drunk driving] go to jail in my court no matter who they are, doctors, lawyers . . . I don't care. People who hit policemen or teachers go to jail.

"But I've been a prosecutor and I know why they are as aggressive as they are. I think one of the reasons it's good to have been on both sides is because you don't get jaded. After you've been a prosecutor for a while you start thinking everyone is guilty. As a judge you don't have to be an advocate. You can be a little more benign."

Today, Chasanow will listen for about four hours as prosecutor Edmond B. O'Connell, low-key and soft-spoken, and defense attorney Bennett, demonstrative and emotional, plead their cases.

Then, he says, he will retire to the quiet of his chambers to make a decision.

"Sentencing is the toughest and most emotional thing a judge has to deal with," Chasanow said. "The first time you sentence a man to jail you lie awake in bed at night and think about it, think about the jail and where you have sent the person.

"But sentencing is a judge's main responsibility and I think you have to adopt the philosophy that you do the best you can. You can't sit around and think for days and days about everyone you sentence.

"You have to be fairly predictable in sentencing. When you get down to it, the final judgment - whether you're sentencing a shoplifter or a murderer - is simple: does the punishment fit the crime?

"That is what I have to decide. That's what I'm paid for."