President Carter's visit has stung the Soviet Union into its angriest reaction for a long time to Yugoslavia's Western ties, especially those with the United States.
In their attacks both Pravda and the Soviet news agency Tass singled out Mr. Carter for supporting Yugoslavia's independence. But the Yugoslavs know the Soviet barbs are aimed at them, too, just as they have been on any occasion in the past when friendly Western connections have seemed to move Yugoslavia still further from the Soviet orbit.
It was the spectacle of Yugoslavia agreeing with the United States in condemning their presence in Afghanistan and so repudiating the Kremlin's "justification" for their invasion that is infuriating the Russians.
Yugoslavia is a communist state, and despite the Yugoslavs' repeated rejection of Soviet efforts to draw them back into the fold, the Russians persist in regarding it as ultimately, "one of theirs" and therefore expected to keep the West at a distance.
Tass called the Carter doctrine of support for independent, nonaligned Yugoslavia "staggeringly importunate."
That is just what the Yugoslavs are thinking of the Russians' angry reactions , particularly as they themselves took care during the Carter visit to avoid anything embarrassing to their always-uncertain relationship with Moscow.
The Russian anger is no doubt prompted in large part by the warmth of the official and public welcome accorded Mr. Carter and by both Yugoslav and US satisfaction in his short visit.
This visit is cementing what both Yugoslavia and the US are lauding as a "special" relationship developed between them over the last few years.
Their officials spoke of wide agreement on may issues. Undoubtedly Afghanistan was foremost among them, although it was not mentioned by name in the joint communique issued as Mr. Carter left.
But the communique does refer to the "inadmissibility" of the use of force and intervention in the affairs of other countries "whatever the form or justification."
That is what the Yugoslavs have been saying quite plainly ever since the Russians moved into Afghanistan, and Mr. Carter's talks with the new leaders in Belgrade have shown they are holding to this position -- and to their call for Soviet withdrawal.
They had no reservations about Mr. Carter spelling it out, as he did both in his speech at the state banquet and in a departure statement Wednesday morning reiterating condemnation of a "gross violation of the sovereignty of a nonaligned state."
Just as forcefully, Cvijetin Mijatovic -- the current president of the new Yugoslav collective leadership -- spoke of his country's total opposition to military or any other kind of intervention in another state.
Mr. Carter's remarks drew a jeering comment from Tass, which asked why he adopted a "pose" as defender of Yugoslavia's independence "on which no one is encroaching?" It accused him of "foisting on it aid and protection" it does not need.
In fact, aid -- either military or economic -- was not referred to in these talks.
As much as possible Belgrade tries to avoid exchanges of polemics with Moscow. But the latter may find the blast at Mr. Carter highly counterproductive where its own relations with Belgrade are concerned.