Protocol is . . .

Conducting affairs of state in a tradition manner dating back to the Vienna Convention.

Letting the ambassador of Nicaragua do everything first.

Conducting affairs of state in a tradition manner dating back as far as living memory.

Accepting the fact that the Volkswagen that regularly blocks your driveway is never going to get a ticket because it belongs to a typist who works at a foreign embassy.

Conducting affairs of state in a tradition manner dating back to the Kennedy administration.

Protocol is . . . none of the above. According to the new chief of protocol, Evan S. Dobelle, it's "what the President and the First Lady do. That's protocol."

And so it is becoming. Having discovered that few of the ceremonial customs practiced in Washington carry the authority of international agreement, or even very long-standing tradition, the Carter administration is gradually changing them.

Nothing really new has been made out of whole cloth. Rather, the old customs are being altered to fit the new President and First Lady.

"We adhering to the basic, simple traditions of protocol," said Dobelle. "It's the embellishments, to my mind, that can be removed. Sometimes they really take away from the dignity. It's almost like a bride going down the aisle in a fur coat and tiara."

With each state visit, the ceremonies have been tailored a bit more.

The first one, that of the Mexican President, was merely cut. The 14 herald trumpeters president Nixon had blasting away from the White House balcony were cut, as were the 50 servicemen parading state teritorial flags, and the playing of "Ruffles and Flourishes" and "Hall to the Chief."

Three visits later, replacement music for "Hail to the Chief" was added. It turned out to be "I'll be Loving You, Always."

It is a policy decision that from now on, Rosalynn Carter and the spouse of the visiting dignitary will stand on the reviewing stand for the ceremonies, instead of at its base, just holding roses and looking up. "We felt they looked kind of shunted off to one side," said Dobelle.

At the first state visit, the President's sister, Ruth Stapleton, said that she or one of Carter's sons would stand in for the President at the second-day party at the visitor's embassy, along with the Vice President. By the British visit, Rosalynn Carter attended and the policy was ammended to say it might be either she or the Vice President.

And the word has gone out that the Carters will not be buying expensive gifts for their state visitors. In past administrations these presents have often been valuable antiques or works of art. Now the gifts will be a photograph of the Carters in a frame with a presidential seal.

Ambassadors are invited to bring their faimilies when they present their credentials. Dobelle then keeps the families company while the formal talks are held.

Dobelle reports that the changes have met with great success. The visitors have "all been estatic. They've all mentioned being at ease. And I've been in government and politics long enough to know when someone's telling me that because I'm chief of protocol, or when they really mean it."

Other protocol matters that are being examined include:

Establishing a non-fault remedy fund for the victims of diplomatic traffic accidents, so that the innocent injured could be compensated without the offending diplomat's having to enter the court system.

Giving the recipients of state gifts some influence in their disposal, although nothing valued at more than $50 may be kept. Israeli Prime Minister Rabin gave Dobelle "a second-century vase which I immediately thought must be worth at least $49.50. Unfortunately, it turned out to be more, but I would like to have it go to the museum of my choice."

Establishing displays of state gifts, so the interesting ones don't just collect dust at the General Services Administration. "But I don't know what we're going to do with the Rolex watches - and we do have a lot of them."

"Looking hard" at the Protocol office itself, to see "if the staff has to be this big. There may be room for reduction."

The question of re-evaluating the ranking system, so that men and women both carry their own rank and not that of their spouses, has not been considered. Dobelle says it could be, but he says it with a smile.

After all, the State Department - where Foreign Service wives fought and won the right not to be evaluated along with their husbands, not to have to participate without pay in their husbands' jobs - Kit Dobelle is working around the clock on protocol matters.

"We were hired as a team," they both say, although it is he who has the title and gets the salary.

He uses the terms "joint appointment" and "two for one" to describe how they share responsibilities - the same terms the Foreign Service wives used in their complaint.

But Dobelle feels the same about members of the Carter family performing official functions. "A family got elected to the White House," he said with more warmth than accuracy, "and a family is serving."

State visitors are being escorted by both Dobelles: heads of state by Dobelle, their spouses by Kit Dobelle. Both the Dobelles are taking Spanish lessons with Rossalynn Carter at the White House solarium (three-hour sessions Tuesday, Wednesday and Friday mornings and plan to join the Carter speed-reading class.

But Dobelle says, "It would be presumptuous to say, we are personal friends of the Carters. I don't know that to be the case. I feel close to him, work for him, I respect and admire him, but I wouldn't impose that on him."

He and his wife do not see the Carters socially, he said, but then the Dobelles are pretty well-fixed for their non-office hours, with state visits and national day receptions at embassies.

"I feel I'm mayor again," he said, in reference to his having served as mayor of his home town, Pittsfield, Mass. "But this time it's to the embassies. There are 22,000 diplomats in this community, and I'm their point man in this country, to solve their problems and make sure their needs are taken care of.

"Fortunately, I don't need much sleep. When you're a mayor, you're used to getting a phone call at 2 a.m. from someone who wants to know why his snow hasn't been removed, or who is taking his coffee break on the night shift and didn't realize what time it was."