Top-flight covert operatives being fired by CIA director Stansfield Turner are convinced that their "Dear John" letters were carefully composed so as to shield the agency - and the admiral - from possible legal action, a protective device that further depresses morale at the Central Intelligence Agency.

The "eyes only" mimeographed dismissal letters, untainted by any word of praise for long service rendered, do not fire anybody. They simply inform the recipient that William W. Wells, chief of covert operations, has an "intent to recommend" dismissal. Further, the word has been passed that those who voluntarily quit after reading their "Dear John" notes will be treated as having made a normal retirement decision, with no damaging words in their files.

This bloodless, self-protective bureaucratic method of rewarding years of loyal service only contributes to the gloom at Langley, where the announced 800 officers (out of 4,500) in clandestine operations to be fired actually will climb to over 1,000.

The cladestine service may indeed have been overstaffed since the end of the war in Vietnam. Old-time station chiefs fired after 20- and 30-year stints admit it. But the pruning of some of the most experienced clandestine agents in the spy business carries implications - denied by Turner's men at the CIA - that Turner is de-emphasizing human intelligence in favor of electronic intelligence.

"The Russians can now blunt our spy-in-the-sky capability," one worried intelligence official told us. "Downgrading the human element in intelligence could lead to one of the great intelligence failures in our history."

Two things infuriate and humiliate the old hands: first, the particularly "brutal" way (to quote one top-level CIA officer) Turner is engineering the separations; second, the danger implicit in stripping top foreign posts (including the highly sensitive post in Bonn) of the best, most experienced operatives in the CIA.

Footnote: Adding a new Byzantine dimension to Turner's undoubted ability to alienate his CIA subordinates is his double-edged use of Wells as chief hatchetman. The word is out inside the CIA that Turner is now looking for the "right" replacement for Wells to run the once-essential clandestine service.

The problem posed by Marshal Tito for U.S. foreign policy was pointed up this year when Yugoslavia secretly sent American tanks to revolutionary Marxist Ethiopia in violation of U.S. law.

In contrast, Yugoslavia refused to break a Soviet agreement last year when non-revolutionary, non-Marxist Egypt requested desperately needed Soviet military equipment. Such contradictory handling of identical requests by Third World countries underlines this problem: How closely should the United States cooperate with Tito - cooperation based on mutual distrust of the Soviet Union - when Tito invariably aids new revolutionary movements abroad no matter how detrimental to U.S. interests?

Both Washington and Moscow ban the transshipment of military equipment they sell or give away. Yet Tito approved the dispatch of M-47 tanks - believed between 50 and 100 - to help the Soviet-allied regime in Ethiopia.

This was discovered, almost accidentally, by U.S. intelligence agents in Africa.

When Moscow denied Egypt vitally needed spare parts for its Soviet-built tanks and aircraft, President Anwar Sadat appealed to Tito during his April 1976 state visit. Tito was deeply remorseful: Sorry, Anwar, I want to do it but I simply cannot break my agreement with the Russians.

Yugoslavia has now quietly apologized to the United States for breaking the transshipment ban. When Secretary of Defense Harold Brown visited Belgrade last month, Yugoslav military officials promised him it would never happen again.

Nevertheless, the record shows that Tito has an irresistible urge to give all aid possible whenever asked by a revolutionary regime. He ignores the fact that the United States happens to be a victim in almost every case, especially so in Ethiopia, where the Soviet takeover threatens Communist domination of vital sea lanes bringing oil from the Persian Gulf.