The battle for full voting representation in Congress for residents of the District of Columbia is likely to be won or lost in places like this city of 50,000 in southeastern North Carolina instead of the hearing rooms of the Senate.

D.C. Del. Walter E. Fauntroy knows that, so he has been spending many nights and weekends in the Fayettevilles of the nation, asking the home folks, especially the black home folks, to put pressure on their home state senators to vote in behalf of the proposed constitutional amendment.

Whether it is here, or Stamford, Conn., where he was Saturday, or San Diego, Kansas City, Austin, Daytona Beach, Atlanta or Columbia, S.C. Fountroy, a master showman preaches, teaches, raps and even sings and dances for his favorite causes, equal rights for District residents and for blacks everywhere.

Back home in Washington, Fauntroy is a serious, dedicated advocate of home rule who last month joined friendly congressmen and constitutional scholars in pleading the case for D.C. before the Senate subcommittee on constitutional amendments. But with Sen. Birch Bayh (D-Ind.) presiding, the hearings were a matter of preaching to the converted.

Invite him to speak at a political rally in the South, as did Kenneth P. Johnson, a black candidate for the North Carolina legislature, and you get a three-ring circus from the District of Columbia's premier preacher-politician.

Fauntroy climaxed an hour-long performance here by singing, a capella, a version of "The Impossible Dream" that brought the audience of 100 to its feet cheering.

Fauntroy had urged the Senate subcommittee to support the election of Senators and Representatives from the District of Columbia, "beacuse it's right, it is a moral issue."

To the largely black audience who paid $12.50 to go through the cafetria line and sit in booths and plastic-topped tables at Jordan's Buffeteria here 10 days ago, Fauntroy preached the politics of opportunism.

Whether it is electing Senators from the District of Columbia or sending K. P. Johnson to Raleigh, Fauntroy said, "black folks have no permanent enemies, no permanent friends, just permanent interests."

He talked about the "new math" of Southern politics that results from 3 million new black voters having registered since passage of the Voting Rights Acts of 1965.

Blacks make up at least 25 percent of the registered voters in 40 Congressional districts in the South, he said, about the same as they do in Cumberland County here, where Johnson was a candidate for the legislature.

The new math was not enough for Johnson who finished seventh in a field of nine Tuesday for the five Democratic nominations to the North Carolina House from the county.

There is plenty of time left, however, for applying the new math to Fauntrop's main concern for coming here, the election of a U.S. Senator in November.

Republican Jesse Helms faces a tough reelection campaign against the winner of the May 30 Democrat run off, and with blacks making up 22 percent of North Carolina's registered voters, the not-so-subtle message is that if Helms wants any share of the black vote in November, he ahd better support D.C. voting representation in Congress, which is scheduled to come up for a vote in the Senate before the election.

Both the conservative Helms and Sen. Robert B. Morgan (D-N.C.) told The Washington Post last month that they are undecided on the issue.

"Write 'em," pleaded Fauntroy. "Just a little note to Morgan and Helms. Don't let them be out of step with 10 of your 11 House members."

When the House approved the issue in March by a vote of 289-127, all but one of the state's congressmen voted in favor of it. Fauntroy singled out for praise Rep. Charles Rose (D-N.C.), who lives in Fayetteville, for playing a "major role" in swinging the delegation in favor of D.C.

The first person to understand the arithmetic of rising black voter registration, Fauntroy told his audience here, was the man who was serving as master of ceremonies, Dr. Claud L. Stephens.

Stephens, a 46-year-old medical doctor and graduate of Howard University, lived across the state line in South Carolina until about five years ago. In 1970, with the campaign help of a busload of District of Columbia residents organized by then-former Councilman Fauntroy, Stephens drew on the 34 percent black voter registration in South Carolina's sixth congressional district to force a runoff with Rep. John L. McMillan (D-S.C.).

McMillan, the self-styled "mayor of Washington" who had blocked home rule for the District of Columbia for decades as chairman of the House District Committee, defeated Stephens in the runoff. It set the stage for 1972, when, Fauntroy explained, McMillan foes "got smart and got themselves a white boy," State Rep. John Jenrette, who beat McMillan in the Democratic primary, and ended his 32-year Congressional career.

[Imitating McMillan's drawl, Fauntroy said the defeated congressman called Jenrette and said, "John, you like to be the Congrman?' (sic) I'll never forget that day. It was Oct. 12, 1972, and I danced the bugaloo in the street."]

Following McMillan's defeat, Fauntroy said, many of the representatives of those 40 districts with critical black registration figures "got the message and called and said, 'Walter, we's always been with you.' And home rule for the District passed the House in 1973."

Fauntroy also traced the increasing black registration figures in the changing attitude of a southern senator, whom he would not name except to say he still is in Congress. In 1963, the senator vowed to "keep the niggers in their place," Fauntroy said. In 1966, with 70,000 newly registered black voters, the senator "expressed concern for the colored folks." By 1968, he was using the word Negro, and, in 1972, with 180,000 new black voters, he announced his concern "with my black brothers and sisters."

That Senator, Fauntroy said as the 80 blacks and 20 whites roared with laughter, "also understood the arithmetic of power."

In that same context, Fauntroy said, "Jimmy Carter is the smartest white man I know." Fauntroy said that when Carter decided in 1970 to seek the presidency, "he didn't go to the Wall Street bankers. He went to Martin Luther King Sr. in Atlanta and said, 'Daddy, I wants to be the president.'"

Fauntroy went on to tell residents in this hometown of June Carter Stapleton, the president's sister, that "hands that picked cotton picked the president. Jimmy are the President and I is happy."

Of his own election to Congress, Fauntroy said, initially "some folks said, 'we don't want a preacher, we wants a lawyer.'"

But he worked hard for the vote of various groups in the city, Fauntroy expalined, illustrating his campaign techniques with vatious speech patterns.

When he spoke at "that bastion of Negro education, Howard University," Fauntroy said he summoned "all my Yale diction," (he attended seminary at Yale), and "when I went to 14th and I - you know where that is, every city has one - I asked all the pimps, all the punks, all the prostitutes and all the preachers to vote for me," he squealed, jumping up and down.

Since his election, Fauntroy said that as a member of the House Banking, Currency and Housing Committee he has learned that "we're not going to take the rich off public welfare." Every attempt the tax structure so that millionaires and multinational corporations pay their fair share of taxes has failed, he said.

"If we wake up every Archie Bunker to the game being run on him and us, he'll realize that busing is not the issue and black is not the enemy," Fauntroy said.

Then it was time for the finale, and Fauntroy implored his audience to share with him "the impossible dream . . ."

As he sang, he held up a chart showing the black share of registered voters in the south, pulled out his wallet on the words "willing to give," and held the audience spellbound.

At the end, as he joked about "signing autographed copies of my album at the rear of the room," George W. Breece, a former aide to the late Hubert H. Humphrey, signed, "he talks longer than Hubert did," but another listener added, "Yeah, and just like Humphrey, he's dedicated to a cause."