William J. Smith Jr., 24, looked neat and unruffled in his jailhouse denims as he sat in court yesterday and listened to the arguments about whether he should be locked up or released until he is tried on a charge of murdering William M. Dixon.

"It was a crime of passion," said James E. Joyner, Smith's attorney. Joyner said Smith was merely trying to protect his mother and sister, and that if Dixon had died on Smith's doorstep "we wouldn't be here now."

"We have five witnesses who saw this carnage," said Bernard Panetta, the Assistant U.S. Attorney. So, far from being a "crime of passion," said Panetta, Smith's alleged act showed "a mental state which would permit one to slowly and deliberately commit murder."

hus did the prosecution and defense state their views of the case to Judge Dyer Justice Taylor of D.C. Superior Court. It was Taylor's job to decide whether Smith was to be held in pretrial detention, or whether he should be released without money bond under the D.C. Bail Reform Act of 1970.

The lawyers did not argue about the facts themselves, only about what these facts meant. Officer McKinley L. Williams of the D.C. homicide squad testified that the facts had been verified by Smith himself:

Dixon, 40, whose nickname was "Demon" and who had a reputation for carrying a gun, broke up with Wanda Harris, Smith's sister, last Monday night. Mrs. Harris went home to her mother's house at 1740 Bay St. SE.

About 8:30 Tuesday morning, Dixon, who lived at 4190 Livingston Rd. SE, went to the Bay Street address. Smith told him not to come in. Dixon reached for the doorknob with his left hand and at the same time made a gesture toward the waistband of his trousers with his right hand.

At that point, Smith apparently thinking that Dixon was reaching for a weapon, allegedly shot him with a single-barrel sawed-off shotgun.

Dixon staggered off the porch. Then he ran along 18th Street SE (the Smith residence is at the corner of Bay and 18th) to Independence Avenue and turned left toward 17th Street. He collapsed in the intersection of 17th and Independence SE.

"Smith walked up to him and fired a shot at him," Officer Williams testified.

Then he broke the shotgun open, took out the spent shell, reloaded and fired another at Dixon. Williams said.

Williams said he went to the Bay Street address shortly afterward. He said Smith told him what he had done even though the officer tried to stop him until he could be sure that he had been advised of his right to remain silent by uniformed officers who already had placed him under arrest.

On Wednesday, Smith was presented before Judge Fred L. McIntyre of D.C. Superior Court on a police complaint charging second-degree murder. The sole purpose of a presentment is to set bond.

On these facts, Judge McIntyre might well have released Smith on personal bond pending further court proceedings, even though the charge was murder. This is because the U.S. Constitution guarantees every accused person the right to bond except in capital cases.

Since there is no capital punishment in the District of Columbia, all defendants are entitled to bond. The D.C. Bail Reform Act of 1970 states that in cases where an accused can demonstrate "strong community ties" - by length of residence, family ties and other factors - no money bond will be set.

Bond is set only to ensure that an accused will appear in court when scheduled. The rationale behind the "community ties" standard is that these ties will insure that a defendant will not flee. Moreover, that standard embodies the thinking in a long line of U.S. Supreme Court cases that say that high money bonds cannot be used to protect the community from a person who may be violent.

In practice, this means that most persons accused of crimes in the District go free until they are tried.

To deny an accused person his freedon pending trial, the government must prove that he has been convicted of a violent crime within the past 10 years, that these is no way of "reasonably" assuring that he will not pose a danger to the community, and that there is a "substantial probability" that the person will be convicted of the offense with which he is charged.

Smith testified at his presentment before Judge McIntyre that he had no prior convictions. But the Career Criminal Unit of the U.S. Attorney's Office discovered a burglary conviction in 1972. McIntyre thereupon ordered Smith jailed pending yesterday's full-scale hearing before Judge Taylor.

Such hearings are rare. Since the Career Criminal Unit was established last August, prosecutors have sought pretrail detention inly 24 cases. It has been granted in 19 of them.

"The government can't show that (Smith) would be a danger to any other person," Joyner, the defense attorney argued.

"It didn't end on the porch," Panetta, the prosecutor, replied. "He stalked (the victim) down the street."

At the end of a 90-minute hearing, Judge Taylor ordered that Smith be held in pretrail detention. The government must bring him to trial within 60 dyas of last Wednesday, when Judge McIntyre first ordered him to jail.

Smith requested through his attorney that he be sent to a facility other than D.C. jail. Joyner said he feared retaliation from friends of Dixon who are inmates.

Judge Taylor granted his request.