One afternoon last December, a Hyattsville lawyer named Richard Palumbo met with Prince George's County Executive Winfield M. Kelly Jr. to talk about an opening on the county's legislative delegation.

Palumbo wanted the appointment and, by most accounts, he had the votes to get it. He was, after all, a member of the Democratic Central Committee, which was formally charged with filling the vacancy.

It was left to Kelly to give Palumbo the word. "Richie," he said, "this is not the time to create dissension in the ranks. You are a good party man. Your time will come."

Kelly does not usually interfere in the selection of state delegates and senators, but this was an exception. His relations with the municipal officials in the northern part of the county were strained. One way to improve things, Kelly decided, was to give the delegate seat to one of these same officials - Hyattsville council-woman Mildred, Harkness.

Through Kelly and other Democratic leaders, some of whom were less diplomatic, Palumbo got the message that challenging Harkness would be a mistake. Finally, at a 22nd District caucus, he got up and announced that, after days of careful thought, he was withdrawing his name from consideration.

In the following weeks Palumbo was hailed by his party colleagues as a "good soldier." Today there is another phrase the Democrats use when they talk about him. "Richie," they say, "has paid his dues."

When it became apparent this week that veteran Del. Ann R. Hull, another legislator from the 22nd District, would not seek re-election, some party leaders decided it was time to reward Palumbo for his loyalty.

"What do you think of Richie?" party chairman Lance Billingsley asked another Hyattsville-area delegate, Charles J. (Joe) Sullivan, at an Indian Springs Country Club reception.

"I think there are a lot of good candidates," replied Sullivan, tactfully.

"Yeah," said Billingsley, "but this is a guy who's paid his dues."

In Prince George's where almost everyone is a Democrat and almost no one can keep a secret, the word spread through the party ranks that Palumbo had a spot on the Democratic ticket.

Billingsley maintains that "the process" (the county Democrat's shorthand for a candidate selection committee) will determine Palumbo's fate. But he does not conceal his preference:

"Richie has worked the precincts for long, long time. As chairman, I feel we first have an obligation to look within our own ranks . . . Richie has done a lot for the party. He deserves a shot."

Palumbo, 30, a short and spirited man who one central committee colleague describes as "the love of the committee," expresses a self-effacing attitude about his dues-paying. "How anybody would associate my name with a vacancy of that kind surprises me," he says. "I'm flattered that I'm thought of that way."

As Plumbo sees it, his decision to avoid challenging Harkness last winter was based on "idealism." "I concluded that I would have other opportunities, whereas Mildred might not," he says. "You can bet one thing about me, nobody dictates to me or tells me what to do.'

Billingsley's open endorsement of Palumbo at this stage - week before the party's selection committee is to be picked and two months before the slate is to be decided upon - has prompted several Hyattsville-area Democrats to question the ipenness of "the process."

"Everytime the leaders say the party's open they turn around and do things like this," says Tony Cicoria, another Democratic candidate for the House of Delegates in the 22nd District. "I don't understand why they even have primaries anymore."

"It may seem like we have an efficient machine," responds one Kelly associate, "but we don't. It's like the Wizard of Oz when Todo (the dog) pulls back the curtain and reveals the Democrat to question the openness of tence. Even if we want Palumbo, something might happen to foul it up."