IN DIPLOMACY, AS IN LOVE, SOME things will never change.

Just about everybody, for instance, strongly suspects that Pakistan has tried to develop a nuclear bomb over the years -- especially since the neighboring states of India and China and the nearby Soviet Union have the Bomb.

But ask Jamsheed Marker, the Pakistani ambassador to the United States, if Pakistan has tried to develop a nuclear bomb and he says, "No, we have not." Then, with a wink, ask him, well, if it were true that Pakistan had tried to develop a bomb, would you lie about it anyway, because that's your government's official position?

The ambassador looks reflective. "This is very much a hypothetical question . . . ," he says. "In answer to your question, if I had the Bomb and I was asked outright and it was not in my government's interest to reveal the truth, I would find some way around it." The people in power in the world, he says, know the truth about Pakistan's nuclear policy, and that's what counts.

Then, with his own kind of wink, Marker says, "On another matter: We have proclaimed publicly that Pakistan is not a conduit for arms to Afghanistan. But you know and I know that Stingers are not indigenous to Afghanistan. You know it, the Soviets know it. But we take a different public position."

Hmmmm. What did English diplomat Sir Henry Wotton say in 1612? "An ambassador is an honest man sent to lie abroad for the good of his country."