THE SOVIETS DENUNCIATION of Santiago Carrillo, the head of the Spanish Communist Party, was full of thunder and lightning. But the chief effect so far has been to offer Mr. Carrillo the occasion to declare, once again, his independence from the Soviet line. He had written a book, "Eurocommunism and the State," that the Soviet magazine New Times reviewed at great length. To be sure that no one missed the review, the Soviets put the full text on the Tass wire. Even the book's title was offensive to the Russians. The anonymous reviewer bitterly accused Mr. Carrillo of using the term Eurocommunism to divide the Communists of Western and Eastern Europe. Worse, he was denigrating the "true" socialism of those countries that have built new societies - the leading example being, of course, the Soviet Union. Mr. Carrillo replied by observing at a press conference, that Stalinism is not dead in Moscow.

The Soviet anxiety over the heresies of the Western European parties seems to be growing in direct proportion to those parties influence. This latest admonition from the Soviet arrived just as the Spanish party was beginning its own assessment of the recent elections there, it ran third with 9 per cent of the vote. Perhaps the Soviets are trying to push the Spanish party in the direction of the Portuguese Communists who, under an unrepentant Soviet-liner, Alvaro Cunhal, seem to be slowly increasing their following.But Portugal, in its poverty and isolation, is not the same country as Spain. As for Mr. Carrillo, he said with a smile that he sees no reason to change his views.

Any Soviet declaration on this sensative subject has to take into account Italy and France, where Communists now appear to be getting very close to participation in government. The Italian party responded with a cautious and gloomy statement pointing out the "ambiguities" in the Soviet attack on Mr. Carrillo. But an international discussion of ambiguities was not what the Soviet Union wanted. The French party's leader, Georges Marchais, remarked that he himself never uses the term Eurocommunism, but in any case his party does not intend to move its position - "not an inch."

It's comic, isn't it? The Soviets' dilemma in dealing with the Communists of Western Europe is the mirror opposite of the Americans dilemma. The United States is dismayed by the rise of the Communist parties in these three countries, but there's very little that it can do. American threats of diminished support or of strategies dangers are merely counterproductive. Eighteen months ago the Ford administration toyed with the idea of putting some money secretly into the Italian election campaign, but the idea blew up with some damage to the people it was supposed to help.

The advance of these Communist parties distresses Americans because they don't see enough evidence of real independence from the Soviets. It distresses the Soviets because they see too much evidence. When they point out that their free-thinking comrades of the West are straying from the one true path, they are repaid with nothing but cutting remarks about Stalinism. There's not much comfort in the thought, but the Russians' methods for dealing with Eurocommunism seem to be even less effective than the Americans.