Out of an old Rambler stopped at 18th and H yesterday warbled: Sweeeeeeeetheart, Wasn't there a moon? Wasn't it in June? I met youuuuuuuuu?

A traffic light or so back at 17th and H, you would have heard "Lay your head upon my pilloooooowww," wafting toward the walls of the Export-Import Bank, and before that, at 17th and K: "Almost heaven, I"West Virginiiiiaaa . . . "

Said the silver-haired man in the Rambler, James Symington: "Some of the corridors of the nation's capital are the greatest acoustical places in the country. My head is just full of songs, and they keep wanting to pop out."

Last night at Charlie's in Georgetown they did, romantic cafe songs from the '30s that made you think of dashing rogues in dim nightclubs. Symington, the LBJ protocol chief and former Missouri congressman who once looked like a dashing rogue you should have met in a dim night-club, sang for 140 friends and fans at an opening that was also, by his decision, a closing. "I'm like the locusts," he said, "I come out once every 20 years."

He's been singing for a lot longer than that, first "Au Clair de la Lune" as an 11-year-old at St. Bernard's in New York, then with the Whiffen-poofs at Yale, then at the Sherry Netherland while at Columbia Law School, then for Queen Elizabeth II as assistant to the U.S. ambassador to Great Britain. And then, in Washington, you could hear him at the embassies, the Shoreham and in front of the fireplace at dinner parties.

On Johnny Carson, too. "The show wanted somebody in government who didn't take himself too seriously," he explained.

He never has. Enormously popular as protocol chief, he's now a 53-year-old lawyer and longtime Washington fixture who can look at this town and laugh. His sense of humor has made as much a place for him here as his voice, his connections and the father who was former Missouri senator Stuart Symington. His great-grandfather was Secretary of State John Hay under Abraham Lincoln, and his mother was Evie Symington, the cafe society singer you once could find at New York's St. Regis and Waldorf hotels.

"My mother had a sense of mischief," Symington said. "Maybe I got some of it from her. You can't let this place get to you. And it helps to have an anchor to windward, too. Being from Missouri, I spent a lot of time soaking up the wisdom from that state."

Two of his laughs from the past:

"Once we flew the British flag up-side down on the occasion of Prime Minister [Harold] Wilson's visit. I got a 6 a.m. phone call from President Johnson who said.

"Have you seen the paper?'

"No, I haven't,' I replied.'

"'I think you should have a look at it,' he said. 'I'll hold.'

"Well, I go out on the grass with my bare feet, the commander-in-chief of the Free World holding. And there on the front page were Johnson and Wilson beside the upside-down flag. The caption said, 'Oops!'

"Well," continued Symington, "I'm not going to tell you the rest of the conversation. Just say I did a lot of listening. But the prime minister said 'Not to mind -- happens all the time.'"

The second laugh, from his first day on the job as protocol chief:

"When the ambassador of Sudan arrived, I didn't know the way to the president's office. I walked him into a broom closet."

Last night at Charlie's, before the first of two shows, he was sucking a lemon. "Greatest thing in the world for the throat," he said. "I brought my own. And I will not throw it."

He opened shortly after 8 p.m. with "Pennies From Heaven," singing in a crisp tuxedo and smooth vibrato to tinkling glasses and hazy light. In the crowd were other Washington fixtures like NBC television commentator Nancy Dickerson and Jack Valenti, head of the American Motion Picture Association of America.

A few lyrics here:

You were destined for purple-hued throne rooms

You were passion for princes to see

Still I keep thinking of you

In my own rooms . . .

There was another show at 10 p.m., and that was it. No repeats, no regular act. "I'd rather be an irregular one," said Symington, who got lured into sing by friends like Ron Nessen, the former Gerald Ford press secretary who owns some of the restaurant.

"This was in lieu of investing," Symington explained. "I'm telling them I'm worth about 10 grand right here. I didn't invest because I didn't know who the cook was."

He sings often in his Rambler, the shower or wherever the spirit moves him. But he's never wanted more than that. "You have but one life," he said, "and there are so many other things that compete. I guess I've been unwilling to turn away from all those other callings to concentrate on music."

Still, he sometimes writes songs. Here's one called "Washington": Washington It's time you had a song From Cardoza to Spring Valley The muse of Tin Pan Alley Has neglected you too long . . . People staring at you What do they see? Here and there a statue Not you -- not me . . . When they've gone Back where they belong Memories remind you Of dreams that came to find you.