The annual picnic of the Asbury United Methodist Church in Brandywine always begins with a homemade parade along Moore's Road where it crosses Rte. 5 and stretches out to clamber over hills and through cornfields. This is deep in southern Prince George's County, where local residents call Washington "town."

County police stopped traffic on Rte. 5 for about 20 minutes last Saturday, backing up cars for miles. The parading crowd -- a clutch of brightly dressed walkers, two dozen young members of the Southern Maryland Marching Band, half a dozen rumbling motorcycles from a club called Family on Wheels and a 30-foot haywagon drawn by four lumbering Belgian horses -- crossed Branch Avenue on that sticky, overcast afternoon to reach the T.B. Ball Diamond, just a few hundred yards west of the four-lane highway.

There were a white Buick convertible, a black Cadillac Eldorado and a shiny red fire engine with a young man standing over the cab, smiling and waving at the overheated motorists and the few spectators along the side of the road.

"Every year I wonder how many of my constituents I am holding up," said County Council member Sue Mills. Dressed in a lime green pantsuit, she was riding on the rear deck of the Buick, which had her name emblazoned on its side.

The stalled drivers might also have recognized state Sen. Tommie Broadwater (D-Landover) in the black Eldorado and Lawrence Hogan Jr., son and aide to the county executive, atop the fire truck.

But all of the dozen Prince George's officials who were invited, including Republican Congresswoman Margorie Holt of District 4, state Del. Joseph Vallario (D-Oxon Hill) and Police Chief John McHale, were glad to be a part of the Asbury church family for a day of back-slapping, softball and barbequed ribs. It is a 15-year-old tradition.

The Asbury congregation is made up of several large black families who are interrelated by marriage and can trace their roots in the rocky soil back to slavery. The church membership wields influence that reaches at least as far as Upper Marlboro and Annapolis.

Most of the politicians were invited by Wilson Moore, the chairman of the picnic committee. Moore is one of the patriarchs of the Moore family which, along with the Ducketts, Brookses, Neales, Hawkinses, Pinkneys, Rosses, Stemleys and other families, makes up the church, which is more than 100 years old.

The extended family has long been active in county Republican politics. In the past, being black, Republican and related has given the Moores and the other families a distinctly pivotal position in south Prince George's politics, whether they vote Republican or split their tickets in this county dominated by Democrats.

Their potential 300 or more votes in the sparsely settled area cannot be ignored. Although recent population growth may be diluting their clout, the strength of the families that make up the Asbury church have made the politicians responsive to the area's needs, whether for a new school or a summer job for a deserving youth.

While insisting that the day belonged to the church, Moore, 74, spent much of it energetically meeting and greeting the "friends of the family" who happen to be county leaders.

True to the political tradition, Sydney Moore III, 19, and his brother Reginald, 18, who were the third and fourth student members, respectively, of the county school board, added a voter-registration campaign to this year's picnic. Republican Wilbur Wilson, who is black and an aide to county executive Lawrence J. Hogan, was only too glad to come down and help out. Wilson estimated that about 35 persons were registered.

"I was glad that a lot of our family and people here were already registered to vote," observed Sydney III.

Reginald, who is natural politician and a state champion wrestler for Swynn Park High School, spent much of the day mingling with the VIPs as well as the family members gathered from all over the metropolitan area, his right hand pumping right hands and his left hand gripping forearms.

County Council member William Ammonett said he always enjoys the Asbury church picnic. "It isn't just because I'm a politician," he said, though he conceded, "They do have a lot of people in any parade, and if you can meet a few people and shake a few hands, that's good too."

Mills said she met Wilson Moore when she was on the school board almost 10 years ago and the Brandywine community was fighting to get a new high school. "They (the Moore family) are active in the community, and when you're active in the community that involves politics," she said.

Both Mills and Ammonett may need all the friends they can get in southern Prince George's because any new County Council redistricting plan, required this year by a charter amendment passed last November, is likely to reduce the council representation from below Pennsylvania Avenue, where they live, from four to two or three members.

But Mills said her biggest kick from her third Asbury picnic came from the hot dogs. "You've got to have a hot dog when you're outside. I was the first one at the window," said Mills. "I was thinking 'hot dog' before we even crossed Rte. 5."

Mills may have been first in line for a hot dog, but she couldn't beat Broadwater and Police Chief McHale to the glistening slabs of spareribs being dispensed from the open-pit barbecue. "I'd have ordered some more ribs but they ran out," said the uniformed McHale. Indeed, chief rib, chef Robert Lucas said although he had prepared about 70 pounds of ribs, he could have used 70 pounds more.

"The ribs are almost as good as the ones in the Ebony Inn," joked Broadwater, referring to the Fairmont Heights club he owns.

It was the first time the county's only black state senator has been invited to the picnic.

"They (the church committee) came up to Glenarden and we talked," said Broadwater, who happened to have in hand a stack of tickets to his recent fund-raiser. "They told me about this beautiful country down here, and I'm glad I came down. It's beautiful country and these are beautiful people."

From under a low wooden frame topped with red canvas and lined with sawdust, the smell of the smoky ribs and two kinds of chicken percolated. At the tables, conversation buzzed with the words "cousin, aunt, uncle."

At least 200 of the 400 picnickers were related, and many of the rest said they always felt like family at the Asbury picnic whether they were blood kin or not.

"I'm one of them," said Gloria Wilkinson of Largo, though she was not quite sure how she was related. "It's an extended family," she said. "A nice warm extended family."

As the sun began to set over the diamond where the cousins were finishing a good-natured but spirited softball game, the church picnic had come off like a soft drink commercial. Sydney III credited the Asbury church with giving strength and focus to its network of families.

"If you look at the black family as a whole, they survive through the church. If you look back from slavery times, that's all we had," he said. "I think we're a strong church; we have a lot of history.

"It's not like when we saw each other every day, like when I was small," he added. "We have to take advantage of every time we can get together like this. It's a must."