It was testimony to the philosophy that politics not only is the art of the possible but can be fun too, provided you don't take it too seriously and your side wins.

The scene was last week's work session of the five-member redistricting committee, chosen by the council to determine the shape and location of nine single-member districts to replace the current 11 at-large council seats. The revamping of the council is the result of a charter ammendment passed overwhelmingly by the voters last November. The session started almost an hour late.

That was the time needed for the three Democrats on the committee to determine that after six months of posing and palaver about geographic balance, minority representation and constitutional tests, they had a plan that satisfied the most important criterion: it could get six votes from the incumbent County Council.

Wearing a grin that connected the freckles on his ruddy face, committee member Thomas Hendershot, the affable New Carrollton lawyer and prime guard ian of Democratic interests on the committee, emerged from a back room on the second floor of the County Administration Building clutching the 13th five-foot-high county map-plan in a series that had papered the conference room walls for the last two months.

Council Administrator Sam Wyncoop, without whose knowledge of the council and county demographics no plan would have been possible, was also grinning as he purposely tacked up the plan backwards before an expectant group of 15 people who had followed the process closely all summer.

The grins told everybody that here was the plan. It was a revision of Hendershot's original offering, dubbed "the Neptune Plan" because it was the result of a lengthy consultation with the sea god, according to Hendershot.

"Maybe he pulled out a mermaid this time," joked committee chairman Hervey Machen as the plan was scrolled out behind him. In fact Machen, the longtime Democratic stalwart who replaced then Congressional candidate Steny Hoyer on the committee last May, had already seen the plan.

After declaiming its virtues, Hendershot noted in a by-the-way manner, "It is my belief that this proposition has a reasonable opportunity for acceptance in the council." The remark prompted guffaws from observers, who sensed that the fix was in.

Hendershot admitted having conversations with some of the council members. Sources close to the process say that while it would have been improper for the council members to discuss what they wanted for themselves in a plan, the basic ingredients for six to eight votes "were just understood."

Hendershot wanted a district that his friend, Council Member Gerard McDonough, could live with. He also wanted to ensure sufficient minority representation on the new council, since three incumbent blacks now make up half the majority needed to win approval from the present 11-member body. Although four plans had been aired in public hearings the week before, only two were at issue going into last Thursday's meeting -- Hendershot's and Republican Ella Ennis's plans.

The Ennis plan put three districts entirely below Pennsylvania Avenue, the psychological Mason-Dixon line for the south county Republican, and three districts with black majorities ranging from 60 to 75 percent. Hendershot's original plan contained a radical proposal that Bowie and Laurel be in one district, which would have established two sure black districts for incumbents Floyd Wilson and Deborah Marshall and a marginally black district in Council Member Sue Mills's Oxon Hill stronghold.

The Hendershot revision took the "Five Towns" area of Mount Rainier, Colmar Manor, Brentwood, North Brentwood and Cottage City out of Wilson's solidly black district, and joined them with Hyattsville, which pleased Machen. It also ran Marshall's district further down the Southern Avenue border of the District of Columbia, pitting her against Mills while at the same time removing Mills from her Oxon Hill base. With black committee member Wayne Curry's concurrence, it left the third sure black seat in the temporary trust of McDonough. McDonough is confident that he can carry the 50-percent-black district based on his voting record.

Severing Bowie from Laurel was seen as necessary to gain the support of Frank Casula, the incumbent from Laurel. But to fit the last piece of the political jigsaw, Hendershot had to marry Greenbelt and the politically dominant Bowie.

Besides stabbing Mills in the back, the plan will also place liberal Ann Landry Lombardi in a conservative Bowie district that is notoriously hostile to outsiders. Quiet Council Member Sarah Ada Koonce will be pitted against her neighboring incumbent, David Hartlove, as an underdog, meaning three of the council's four women may not return after 1982. With the exception of Roy Dabney, who as a black has been counted out of the running in his native Bowie, all the remaining council members are considered protected by the plan.

Dealt out of the game by this political sleight of hand, Ennis cried foul.

"This is supposed to be a serious procedure, not one designed to protect incumbent members of the council," said Ennis, who recently resigned from a political job in County Executive Lawrence J. Hogan's office to consider running for an undisclosed office.

But while a Republican in the audience muttered angrily about democracy and a representative of the League of Women Voters rolled her eyes toward the ceiling, Machen, who had been playing the role of a neutral link between Hendershot and Ennis all summer, began to attack her plan in good democratic fashion and the issue was decided.

"It's very nice to say that politics don't exist," Hendershot told Ennis gently, "but I think that's not to live in the real world."