At 10:46 yesterday morning, for the first time since the mayor's case began, Deputy U.S. Marshal Albert Crew had a prisoner.

Crew slipped wordlessly into position behind D.C. Mayor Marion Barry's left elbow, the position they teach you in marshal school, just as U.S. District Judge Thomas Penfield Jackson completed the phrase, ". . . is hereby committed to the custody of the U.S. Bureau of Prisons."

Seconds later, just as quietly, Crew retreated as Jackson said Barry may remain free on his own recognizance until a place of confinement has been specified and Barry's expected appeals have run their course.

Barry may not even have noticed that he was in custody. But the moment, however transient, stood graphically for the outcome of the most important question in yesterday's proceeding: Would Barry be sentenced to prison time?

How Jackson came to his answer undoubtedly will be the subject of legal and political debate. Harvard law professor Charles Ogletree, a former public defender in Washington, was among the early critics yesterday who found the sentence, "compared to other sentences of people equally situated, to be surprisingly harsh."

But an important question for the judge was, who is equally situated? To those who complain that Barry, convicted of a single misdemeanor, was treated more severely because of his high position, Jackson's reply was succinct: He was.

"Of greatest significance to me in sentencing this defendant is the high public office he has at all relevant times occupied," Jackson said in the opening words of his order.

Jackson did not make the specific legal finding, as the prosecution urged him to do, that Barry had breached his public trust by using the instruments of his office to obtain illegal drugs. But he did adopt the argument, voiced by Assistant U.S. Attorney Judith E. Retchin, that "because of the defendant's unique position, he's not an ordinary misdemeanant."

The judge put his stamp on a metaphor used by Retchin in her closing argument in August. Where the prosecutor likened Barry to a general who turned against his troops, Jackson used language drawn from the constitutional definition of treason. Barry, he said, "has given aid, comfort and encouragement to the drug culture at large, and contributed to the anguish that illegal drugs have inflicted on this city in so many ways for so long."

In one sense, there is nothing unusual about the judge basing his sentence in part on factors beyond the crime for which Barry was convicted.

It has been basic federal doctrine for many years that a sentencing judge may consider a range of facts and allegations. Summarizing that discretion, the U.S. Supreme Court said in 1972 that a judge is "largely unlimited either as to the kind of information he may consider, or the source from which it may come."

Sentencing guidelines that began to bind federal courts in 1987 made uniform rules to codify that doctrine.

A judge may consider only "reliable" information in fashioning a sentence. Four federal appeals courts have interpreted that requirement to mean that there must be a "preponderance of the evidence," or evidence making it more probable than not that the defendant committed every act that influences his sentence. That standard is less strict than the "beyond a reasonable doubt" standard that is needed for a criminal conviction.

Although there were limits on Jackson's discretion -- no matter what, he could not sentence Barry to more than the one year for cocaine possession -- he could and did make "findings" that Barry had done things of which the jury did not find him guilty.

"Here is the mayor of the nation's capital in the context of a drug epidemic," said Donald T. Bucklin, a D.C. lawyer experienced in criminal law who thought Jackson's broader focus was appropriate. "He didn't steal any money, but he did something as onerous."

It was striking nonetheless, to some observers, how completely Barry's sentencing was dominated by evidence of what lawyers call "other crimes."

The best efforts of Barry attorney R. Kenneth Mundy could not attract the judge's attention to the charge for which Barry was convicted: possession of cocaine at the Mayflower Hotel one weekend in November 1989.

"On this one occasion he went alone to Doris Crenshaw's room," Mundy said of his client. "He was not on duty. It was a holiday."

How then, Mundy asked the judge, could the mayor have betrayed a public trust? And even if he had, Mundy asked, was the question really for Jackson to decide?

"I don't know what the electorate is going to do on Nov. 6," Mundy said, referring to Barry's bid for an at-large seat on the D.C. Council. "But it's for the public to judge Marion Barry on his breach or violation of any trust."

Both the judge and prosecution steered clear of comment on the election. Neither accepted Mundy's view that the government's evidence of perjury and a six-year drug conspiracy was unreliable.

Mundy based his argument on the jury's deep divisions on 12 of the 14 counts in the mayor's indictment -- "a veritable even split, if we can believe The Washington Post."

The Post reported in August, on the basis of juror interviews, that nine of the 12 unresolved charges, including all three felony charges of perjury, divided the jury 6 to 6 or 7 to 5. Another charge split the jury 9 to 3, still another 10 to 2 and one was never put to a formal vote.

Jackson, who took a passing swipe at the jury's indecision, made his own assessment of the evidence. Barry's drug use with Crenshaw, Jackson said, "was neither his first nor his last such offense," and Barry gave false grand jury testimony in what amounted to "a willful attempt at obstruction of justice."

The weight of Jackson's emphasis on other crimes, said defense lawyer G. Allen Dale, was uncommon.

"Not as uncommon as a person going to jail for a misdemeanor," Dale said. "But still uncommon."