As retiring Police Chief (and avid boxing fan) Burtell M. Jefferson was delivering a final left jab to the jaw of the assembled press at the Municipal Center last week, accusing reporters of spreading "half-truths and untruths" about his decision to leave the department, the rest of the police brass was busy doling out cheerful greetings, hearty handshakes and toothy smiles.

With the announcement last week by City Administrator Elijah B. Rogers that it is "reasonable to assume" Jefferson's successor will come from within the department, there was plenty of reason for the cotton-candy demeanor of The Men Who Would Be Chief.

The new chief will inherit the power and prestige that comes with being guardian of the public safety in the Nation's Capital. But he will also have to balance on a narrow perch between a mayor determined to see the department shrink and rank-and-file officers who largely believe that the mayor is not on their side. Although Jefferson denies it, sources say these same pressures hastened his decision to leave the force after 32 years.

Ivanhoe Donaldson, Mayor Marion Barry's chief political aide, once remarked that the difference between Barry and Jefferson was that Barry was a politician while Jefferson was "the head of a paramilitary organization." Police chiefs always face pressure from the men and women in their departments; but in the case of Washington, department sources say, the pressures have become particularly acute.

The nosedive in morale in the department in recent years, sources say, roughly parallels the shrinking of the force from its Nixon-inspired apex of 5,100 officers in 1973 to 3,361 today.

The department enjoyed sacred-cow status in those days. "These officers are used to having a lot of people, a lot of equipment and money to burn -- like we had back in the early '70s, when people were calling Washington the 'Crime Capital of the Nation' and all that," said a high-ranking official of the department. "All of a sudden, you've got to cut back. The guys are reacting to that."

When Barry visited the 3rd District police station last year, which includes the dope-and-prostitution-ridden 14th Street corridor, he was greeted by an angry chorus of complaints. Officers said money for equipment had been cut back so far that they couldn't keep their patrol cars operational. They said there wasn't enough officers to control the city's rising crime rate. They blamed Barry for not giving them a 9 percent pay raise, like federal workers. Some old-timers recalled Barry's days as a street activist in the 1960s, days in which he and the police were often antagonists.

Jefferson was forced to implement Barry's cost-cutting measures while at the same time striving to keep the trust of his officers. And the new chief faces more of the same, as the city's finances do not promise to improve substantially in the coming years and crime shows no willingness to abate.

"The chief (Jefferson) faced monumental problems," said another high-ranking city policeman."I hope the officers come to realize that he did a good job under incredible circumstances."

Barry's choice of a new chief will go a long way toward determining the future morale of the department. Officiers were reassured by Rogers' willingness to virtually rule out an outsider, and now hope officials will choose someone who will be on "their side."

Race is the unspoken issue. In some circles, it would be political suicide for Barry to choose a white chief. The officers most frequently mentioned as a possible permanent successor to Jefferson are all black, and there is no indication that Barry intends to ignore political reality.

Still, that doesn't stop the gallows humor. "I just met the new chief," goes the joke around police headquarters these days. "She's white."