"You're the one I've been waiting for," said the president of the United States. Dolly Parton, all wiggly ectoderm and technicolor splendor, had just stepped in for a picture.

SMM-aack: right on the lips he got her. Or they got each other -- it was a little hard to tell. At any rate, the buss was accompanied by a half-swooning Valentino embrace. And Rosalynn was standing right there in the receiving line beside her husband looking pleased as punch.

You've come a long way, country music.

"Get a good'un now," said Dolly, after she had surfaced, exaggerating her accent. She was speaking to the herd of near-panic-stricken photographers restrained a few feet away by a rope. "My husband wants a picture of this, too."

"It's the wrong time to bring up your husband," deadpanned the president.

This historic moment took place yesterday at noon outside the Diplomatic Reception Room on the ground floor of the White House. It was only one loud roman candle in a day-long, night-long Fourth of July to country music, with everybody from John R. Cash, the legend in black, to Eddie Rabbitt, the newest rage, from East Orange, N.J., on hand to celebrate.

October is officially Country Music Month. Ford's Theatre is trying to raise a million dollars. Jimmy Carter wants to be reelected. Yesterday all three constituencies got together. The day was capped by last night's black-tie show at Ford's Theatre, with guests paying $250 a ticket. A two-hour highlight of the show is to be telecast on NBC Oct. 16 at 9:30.

You would have thought it was Hollywood and the Academy Awards at 10th and F Street last night. Tinseltown for a night. Limos crating the great and near-great began purring up outside Ford's a little after 6:30. There were police barricades and squad cars and guys talking into their shirt pockets and gawkers by the curbful -- including Joanne Vaughn of Baltimore, who was on her way to Union Station and wondered what all the fuss was. Turns out she adores Glen Campbell.

The stars would emerge from the inky depths of their glossy cars. This would set off screams from the crowd. Then paparrazzi photographers would swarm. When Campbell arrived, he began working the crowd with handshakes. Was he running for something?

Then came Charlie Rich and Mel Tillis and Johnny Cash. Cash, who looks every day of his age, whatever that is, twitched like a jumpy cat before the popping bulbs and practically caused a riot. Five feet away, Sen. Howard Baker (R-Tenn.) entered Ford's with his wife -- and almost nobody noticed. One photographer took his picture. It was just about that way, too, for Jody Powell and Robert Strauss.

It wasn't God who made honky-tonk angels, and it wasn't Hank Williams who brought this music uptown and into things like politics. Or rather, to the edge of town, from the creaky old Ryman Auditorium at 4th and Broad in Nashville to the $15-million extravaganza called Opryland out by the expressway. That was five years ago, and some say country music hasn't been the same since. If the Ryman was the temple of the faith, Opryland and what it stands for are country music's brave new now. You could sense that yesterday.

At noon, it was klieg lights and starched Marines in white gloves introducing stars like Tom T. Hall and his wife to the president. Hall showed up for lunch at the White House in a three-piece powder blue pinstripe suit and a rep tie. He looked like a banker or maybe somebody who's made a pile breeding Tennessee Walkers.

Where were the boys in spangled suits with shining steel guitars, singing lines like "Folks back home think I'm big in Dee-troit City? By day I make cars, by night I make the bars." This could have been the national in-surance lobby.

Actually, Jimmy Carter and Tom T. Hall needed no introductions. "Tom, good to see you, man," said the president. "Come on back down to Plains and see us."

After Hall came Bill Monroe, stepping in for his quick snap and smile. Monroe is a near-40-year legend in bluegrass, up there in the pantheon of country greats with Ernest Tubb and Jimmie Rodgers, the Mississippi blue yodeler.

Only yesterday, he looked like a mortician. Monroe had on black hornrims and a black three-piece suit. His smile was ill-fitting. He is from Roseine, Ky., son of a scrub farmer and coal miner. When you ask him how long he's been playing the Opry, he says, "Son, since 19 and 34." Yesterday, Bill Monroe, minus his Bluegrass Boys, sat at a round table in the State Dining Room eating filet mignon and raspberry mousse off the Johnson china. His table guest was the president of the United States.

Later, during a rehearsal for the two-hour show at Ford's Theatre, Monroe said of his table partner: "Well, he talked about different things, about places in the world, about Georgia. There were some peanuts on the table, and I asked him was they growed on his farm. He said he hoped they was."

At last night's gala, Jimmy Carter came onstage shortly after the big-production-number opening. Country music is about "sad times, bad times, wasted dreams . . ." he said. It sounded like a country song. The music still expresses the simple emotions we all share, the president said.

At that moment, backstage, Dolly Parton, that simple girl from her simple Tennessee mountain home, was being worked on furiously by not just one, but two female no-nonsense makeup artists. One of the make-up women had cowboy boots and a GI haircut; the other was in a very chic Mafia suit. They were about as country as Zbigniew Brzezinski, who was in the audience. The women ruffled the lacey valentine hearts attached to Dolly's arms, fooled with her hair. When the president introduced her she ran onstage. But there was no repeat, alas, of the earlier presidential smacker, just the swiftest brush of kiss. TV has a way of inhibiting.

There seemed a camouflaged chaos to last night's taping, which ran well over the two hours NBC will allot to it Oct. 16. Backstage, a burly man who must have been a producer or a director was saying with immense authority to no one in sight: "It's gotta be hubba, hubba, hubba, okay? Okay. If these stars don't want to come out of their dressing rooms on time, we cut them. Just like that. Okay? Okay."

It may have been no more than weepy-eyed nostalgia, but there were moments last night, when historic old Ford's Theatre, with its wooden balconies and foreshortened house, was an eerie reminder of the sainted Ryman Auditorium. They had the state doors flung open, and if you looked out, all you could see was brick wall in the darkened city. At the Ryman, pickers and singers would exit the stage door after their number and go straight into Tootsie's Orchid Lounge across the alley. Tootsie's -- and Tootsie -- were so famous that there is even a country song called "What's Tootsie Gonna Do When They Tear the Ryman Down?"

The Carters shared the front row of Ford's with House Speaker Tip O'Neill and his wife, Mildred, and Tennessee Sen. Howard Baker and his wife, Joy. In the row behind set the president's national security adviser, Brzezinski, getting his first full dose of country music and afterwards proclaiming "from now on I'm a country boy."

What kept ringing in one observer's head was the line from a Waylon Jennings tune: would ol' Hank have done it this way? The Saturday night Hank Williams first played the Grand Ole Opry, the crowd had to bring that scared 26-year-old back six times for encores of "Lovesick Blues." He kept singing, and they kept clapping, and if you listen, you can still hear the tune wailing lonesome as a train whistle from the pages of a yellowed 1949 calendar. It tells a story, in a way, of someone who had it all, then lost it, as Williams did, in the back seat of a Cadillac, with booze and pills, on New Years Day 1953, just 29 years old, the life gone, the legend born. That kind of hurting is what country music is about.

Only now, it doesn't seem so hurting anymore. Yes, sure, some of them still wear knuckle-sized rings and sing about D-I-V-O-R-C-E ("becomes final today"). But there are also three business managers and two agents for every star these days. Yesterday, Glen Campbell came to Washington, along with Stan somebody, who had slick L.A. talk and manners. Campbell himself met the president at lunch yesterday in a rich blue suit with a little flag of white hanky jetting from the breast pocket.

And yet there was a blind Ronnie Milsap, in his violet glasses with jewels in each lens; and Dottie West, in her waterfalls of auburn hair and her slinky, pistol-legged day-glo pants to match; and Roy Clark in his chocolate shirt and his chocolate tie and his manila suit with brown piping.

Johnny Cash met the president yesterday. Dyess, Ark.'s favorite son came along with his aged mother, his carrot-topped young son, John Carter Cash, and his wife, June. June Carter Cash looked hotter than a pepper sprout, to rob from a song of hers and her husband's. She had on a wild red hat.

"Come back over here where you belong, June," Jimmh Carter said to her during the "photo opportunity" before lunch.

She wiggled in next to the president. He encircled her waist. "Thank God I'm back among Carters," she said.

The entertainers found out at lunch that Monday had been the president's 55th birthday. One of them called out to him, "We ain't had time to get you nothing." "There's still time," the president said. With that, the whole crowd broke into a rendition of "Happy Birthday," and June Carter, who claims she's a distant cousin of the president, presented him with a gold necklace she was wearing. Freddy Fender, following suit, removed his hand-tooled belt to give to Carter.

In the afternoon, during rehearsals, Freddy Fender talked about his bus, "Old Blue." What is a country music star without his bus? This one, a '69 Flexible, with a Detroit diesel, used to belong to Tanya Tucker, and before that Sonny James. Got 10 bunks in it. Fender wanted to put a sign on the door saying "If this bus is rockin', don't bother knockin'. His wife wouldn't let him.

"I'm from San Benito, Tex.," Fender said. "That's down in the Rio Grande Valley. I live in Corpus Christi now, which is about 100 miles from San Benito. See, I like to be close to where I come from. Sort of like migrating birds, you know?"

Fender said this propped back on a chair at Ford's Theatre. He had on the straw cowboy hat that he had worn earlier at the White House. He said he had bought the hat in Robstown, Tex., wherever that is. To his enormous credit, he said he had no desire to go to lunch looking out of time, out of place. He just looked Freddy.

Most of the crowd went from Ford's to a supper dance at the Corcoran Gallery of Art, where round tables were set up in the atrium and several upstairs galleries. Some of the entertainers showed up, too.

Dottie West said she knew the audience was going to be different -- "not our usual fans, you know" -- but she had been unprepared for the "energy" she felt. And the crowning point came for her when she looked out and saw "our president singing right along with me" when she did her number, "My Sunshine."

Freddy Fender thought the president looked very relaxed considering the fact that "he's the director of an insane asylum and deserves the sympathy of the whole world." As for what the evening at Ford's did for country music, Fender answered a question with a question: "Is the pope Polish?" and "Are pork chops greasy?"

House Speaker O'Neill and his wife, Mildred, who chaired the committee putting on last night's benefit gala, were among the last to leave the Corcoran. If there had been any question about President Carter's reaction to the event, O'Neill dispelled it. "He loved it," said the Speaker, "he really loved it."