TDear Beverly,

Well, the Great Destabilizer, Popsie Tribble, dropped over yesterday, and after 15 minutes' conversation, I realized that you and I are mere corks upon the water. It's Popsie who's riding the wave.

"Wife of" hasn't spoken to Popsie for quite a time. I've been following Mr. Ambassador around in California, eating underdone duck breasts and warmed goat cheese salads. But that's not really the reason I haven't seen her. Popsie only likes to touch base every few months. As she explained when I first arrived, "In Powertown, it's best to keep your friendships casual."

I didn't know what she meant then but I think I do now. This is a town where status shifts so swiftly that a euphoric Powerful Job who never had time to return his phone calls can easily turn into a decompressing Used- To-Be-Close-To whose telephone never rings. If the Tribbles become too friendly with an Important Job who loses his power, it's awkward for Popsie to explain to the "wife of" why she dropped them from her party list.

When she did come over, Popsie certainly looked tip- top in her fawn leather pant suit. "I'm going through my renaissance period," she said happily. "I bought this in Milan, size 6."

"You look like Tina Turner," I said. "Did it cost a lot?"

"Not as much," Popsie said, "as buying the property next door to us in Georgetown and making it into tennis courts, which will help Dexter in his new job."

Beverly, I didn't know Dexter had a new job. I assumed that it must be far more lucrative than being a Roving Ambassador.

"Has Dexter left the government?" I asked.

"Not at all," Popsie said. "It's still a secret but he's going to be a Special Assistant in the White House. There's even talk of installing a bathroom in his office, which is next door to You-Know-Who."

I was mystified, and asked, "You mean he's had such an upgrade in salary that it will pay for the tennis courts?"

"Certainly not," Popsie said. "But now Dexter can play with the vice president, and all the media stars want to book a court on Saturday afternoon. Our courts will be the foremost source of leaks in Washington. Too bad you and Mr. Ambassador don't play tennis. You know what they say: 'No tennis. No access.'

I was downcast. It would have been nice for Mr. Ambassador to start his telegrams with, "While I was playing singles with the vice president, I learned that . . ."

But I still couldn't figure out about the money. "How are you going to pay for all this?"

"From the advance I've received on my book," Popsie answered.

"What book?" I asked. "You've never written anything in your life except a thank-you note."

"It's called 'Partying to Win,' and it's subtitled, 'Social Triumphs of a Washington Hostess.' I hope they don't start video taping before the courts are finished."

"Why not 'How to Win New Friends and Drop Old Ones'?" I asked.

"Now don't be sour," Popsie chided.

"How much have you written?"

"I don't have to write it," Popsie explained. "All I do is talk into a tape recorder. Some editor will figure out about the paragraphing and things like that."

Beverly, you know that I've done some professional writing, so I was a bit dashed, especially when she said, "Actually, the video tapes are more important than the book. My agent believes they'll reach a larger audience than Jane Fonda's exercise tapes. All those Yuppies out there want to know how to fold a napkin."

"You don't know how to fold a napkin," I said. "Your housekeeper does it."

"That's why they gave me such a large advance," Popsie explained. "I have to give her a cut. But only on the book rights."

"Even if you haven't written the book, you must have some kind of outline in your head," I said.

Popsie thought a bit. "I've a couple of chapter headings. How about 'What to Serve at Apr the-Record Conversations'?"

"Double vodkas, I assume . . ."

"In the middle of the afternoon?" Popsie replied. "You still don't know much about Washington, Sondra. Iced tea or light beer are the only permissible beverages. Powerful Press and Powerful Jobs never get drunk with each other before the sun goes down."

"Do you have any other ideas for your book?" I asked.

"How to cope with ambassadors' wives."

"What do you mean, cope?"

"They're always asking you to boring fashion shows, luncheons, documentary film showings about their countries. A 'wife of' a White House person should never play favorites. It's best to avoid 'wives of' ambassadors completely, except if they give a lunch in honor of me."

"You mean you'll never come to the embassy unless I give a party in your honor?"

"You're different," Popsie said. "I've known you such a long time that you come into the classification of an old friend."

Beverly, I was not sure this was one of Popsie's High Priority categories.

"Just let me see your guest list beforehand," she continued. "If you're inviting someone more important than Dexter, we'll do our best to come."

"What do you mean, 'do your best'?"

"Try to be flexible," Popsie said soothingly. "Allow me the privilege of choosing my dinner partner. You know what I mean: Someone who might be helpful to Dexter or a Famous Name, so they can take pictures of me with him for W."

Beverly, I suppose Popsie will always be asked to my parties. But I just might switch her place card at the last minute and sit her next to that dusty diplomat, Baron Spitte.

Your best friend,