Robert Redding, the popular but reluctant chairman of Prince George's County's legislative delegation, decided last January he would try to retire from that post without prompting one of the Machiavellian political episodes the county's Democrats usually engage in when any sort of power changes hands.

Redding told the county's 24 delegates he was intent on stepping down as chairman, that he would not attempt to name a successor and that they had less than three months -- until the end of the legislative session last April -- to complete their wheeler-dealing and agree on a new leader.

He should have known his orderly plan wouldn't work. Not only did the delegation fail to choose a new chairman by April, but the members spent the entire summer scheming and bargaining and knifing each other over the somewhat token position. Finally, they managed to lure the county's old, iron-plated Democratic fathers into holding one of their exclusive meetings -- the kind of meeting, that is, where people such as former county executive Winfield Kelly Jr., former Senate president Steny H. Hoyer and former party strategist Peter O'Malley call the shots.

The decision reached at that colloquy -- and confirmed the following day at a delegation meeting in Annapolis -- was that Redding would remain chairman after all. Officially, nothing had happened. But the 10 months of behind-the-scenes intrigue that preceded Redding's unanimous reelection was one of the more remarkable instances of Prince George's-style politicking in years, showing as it unfolded how deeply divided the party has become since its leaders officially retired two years ago -- and how much power those old warriors still can wield.

This byzantine struggle was ridiculous to many because so little seemed to be at stake. After all, the chairman of the Prince George's legislative delegation, as one delegate pointed out, presides over such weighty matters as "whose secretary gets which parking space." But there were several delegates who thought if they could win the position, they could use it to hustle themselves into higher office or the county party's inner circle.

Much of the quiet campaigning through the spring and summer revolved around two candidates. One of them was Lorraine Sheehan, a bespectacled woman known in Annapolis principally for her advocacy of feminist issues and identified in the county with her opposition to the proposed Metro line to Rosecroft Raceway. The other was Frank Pesci, a rotund statehouse veteran who, unlike Sheehan, was battled frequently with the party establishment. Both Sheehan and Pesci are aggressive legislators who have considered running for state Senate in 1982.

When neither Sheehan nor Pesci seemed able to collect enough pledges from their colleagues to guarantee a victory by early summer, various other figures began to maneuver into the running for the chairmanship. Among them were Gerard T. Delvin and Charles J. (Buzz) Ryan, both of Bowie, and Frank Komenda of Camp Springs.

By the first of July, Pesci was frustrated enough to call his by-now bitter rival Sheehan, and arrange a meeting at the Little Campus Inn in Annapolis, a favorite Prince George's hangout. That encounter led, in turn, to a second meeting with Ryan and Komenda at the Bob's Big Boy in New Carrollton.

It was in the second meeting that a deal -- the first of many -- was struck.

Pesci would become chairman for one year, with Sheehan as his vice chairman. In the second year, Pesci would step aside and Sheehan would rise to the leadership role with Ryan as vice chairman.

Before long, however, Sheehan and Ryan decided to back out of the treaty. They claimed Pesci could not produce the votes necessary to guarantee his side of the bargain. Pesci responded by heating the county's phone lines with charges of treachery.

Meanwhile, all sorts of unlikely characters jumped into the cloakroom. On Sheehan's side were state senators such as Thomas V. (Mike) Miller, who encouraged his friends in the delegation to follow his wishes. Kelly, in his first foray onto the county's political scene since his 1978 election loss to Republican Larry Hogan, also actively backed Sheehan. Steny Hoyer, another golden boy who "retired" in 1978, counseled Sheehan and tried to keep track of the votes in her favor.

That brings us to Peter O'Malley, the almost mythical party tactician who withdrew from politics several years ago after putting together what remains of the current party organization, earning in the process a label as the county's "machine boss."

O'Malley was unhappy with Sheehan because she had attacked the County Council for rerouting the proposed Metro F Route from Branch Avenue to Rosecroft Raceway. O'Malley is Rosecroft's attorney. When O'Malley called Sheehan to say he was disturbed about Sheehan's campaign, which included direct attacks on O'Malley, Sheehan, by several accounts, replied, "Peter, you're out of politics. You can't help me anymore."

Sheehan, who says she called O'Malley a month ago to assure him she wanted "to continue to work with him," now denies making the statement. "Why would I say that?" she asked. "That would be a very stupid thing to say. Peter O'Malley is a very powerful man."

What happened next is a subject of much discussion in Upper Marlboro these days. What is clear is that 10 days ago, on the eve of the much-delayed vote to fill the delegation chairmanship, a familiar group of politicians met first in O'Malley's office and later in Hoyer's. None of them was a candidate for the chairmanship. In fact, none was a delegate. But in the best tradition of Pince George's County politics, their discussion sealed the debate over who would be the next chairman.

O'Malley was there to say he was not opposed, as several Sheehan backers were contending, to Pesci's elevation to the chair. He did not want to be used as a factor in any movement to bring Sheehan to the chairmanship.

It is for nothing that O'Malley is considered the county's most adept practitioner of political arts. In this case, by coming to Pesci's defense, he was effectively letting his friends know he found a Sheehan chairmanship distasteful enough perhaps to push O'Malley into making alliances in their opponent's camp.

Gerard T. McDonough, representing several members of the County Council, was there to grumble about Sheehan's personal assult on him and other council members over the Metro-Rosecroft affair. He said the council didn't like Pesci, either.

Hoyer and Miller were there because they had supported Sheehan. Kelly and state Sen. Tommie Broadwater were there also, mostly because they are always included in such affairs.

The group decided Bob Redding would have to remain chairman, since neither Pesci nor Sheehan was acceptable to the six men -- or to the delegation at large, for that matter. Redding wasn't at the meeting, and might have argued against such a decision had he been there. But he was not setting the course.

When the meeting was over, Hoyer called Sheehan to tell her she must step out of the race. Kelly called Ryan to deliver a similar message. And Sheehan, knowing the "Word" had come down, called Redding to ask him to consider another term as chairman.

Redding, who is perhaps the only universally respected member of the delegation, reluctantly agreed. "So we have peace in our time once again, and all that kind of stuff," one delegate concluded with a sigh.