Zbigniew Brzezinski, President Carter's national security affairs adviser, is described as "a second-rate thinker" bent on self-promotion in an article by former State Department spokesman Hodding Carter.

Writing in the February issue of Playboy magazine, Carter repeatedly expressed his disdain for Brzezinski and accused him of contributing heavily to the widespread impression at the end of the Carter administration that American foreign policy is in total disarray.

In the end, however, Hodding Carter blamed President Carter himself for failing to step in and quiet the conflicting voices that proved so debilitating.

"Ultimately, what was most harmful to the administration's standing at home and abroad was the president's almost willful inconsistency," the former press spokesman for former secretary of state Cyrus R. Vance wrote.

"He [the president] would choose the Vance position one month and the Brzezinski position the next. He could send State Department officials out to sell the neutron bomb to our European allies, then publicly decide against its production while they were out selling. Much the same thing happened with the Olympic-boycott decision, announced shortly after out allies had been told it wasn't in the cards."

Hodding Carter, however, professed both sympathy and affection for the president and for Vance, who "wouldn't fight dirty if his life depended on it." He reserved his most scathing words for Brzezinski, who "apparently thought of himself as another [Henry] Kissinger" although he had "neither Kissinger's intellect nor his political savvy."

Even so, by the Playboy account, Brzezinski managed to use his immediate access to the president as a key tool in undercutting Vance and keeping up "what became a single-minded pursuit of dominance in the foreign-policy area."

According to Hodding Carter, the president repeatedly assured Vance that "he, Cy Vance, was the principal foreign-policy adviser," but the president never publicly chose between the two men.

Brzezinski, meanwhile, "never accepted a defeat as final or a policy as decided if it did not please him," Carter said. "Like a rat terrier, he would shake himself off after a losing encounter and begin nipping at Vance's ankles, using his press spokesman and chief deputies as well as himself to tell the world that he had won or that only he, Zbigniew Brzezinski, hung tough in the national-security game as a foreign-policy realist."

Carter said he found it difficult to know why and how the president placed so much value on Brzezinski. The former State Department spokesman, who resigned this year two months after Vance did, assailed Brzezinski as "a second-rate thinker in a field infested with poseurs and careerists," a man who "never let consistency get in the way of self-promotion or old theories impede new policy acrobatics."

By way of illustration, Carter cited the president's May 1977 speech at Norte Dame with its themes of concern for the Third World, arms control and human rights.

At first, Carter said, "Brzezinski let it be widely understood that the key phrases were his own," but then, as concern for the main themes gave way to fears about Soviet expansionism, "the word somehow began to get around that he [Brzezinski] had fought to the last against the fuzzy-minded sentiments voiced at Notre Dame."

Offering an often wryly stated look at "Life Inside the Carter State Department," Hodding Carter confessed that he was sometimes the last to hear of important developments such as last April's aborted raid on Iran. He said he assured an audience in Honolulu that the time had not yet come for military action, only to be told by a flight attendant on the way home about the failed mission.

"What raid?" Carter recalled asking. The attendant, he said, replied: "Oh, God, I think you had better talk to the captain."