What do you mean, a `private' operation?

THE shooting down in Nicaragua Oct. 5 of a C-123 cargo plane loaded with guns, ammunition, and three Americans (one of whom survived and is talking) raises two questions. The first concerns the competence of the Central Intelligence Agency in clandestine operations. The second is the wisdom of such operations. On the first point, this was a bungled operation. It violated the first rule of clandestine operations -- plausible deniability. There are plenty of denials. They are not plausible.

Here was an aircraft that has on the public record flown CIA missions. It flew out of Miami under the label of Southern Air Transport, a charter line once owned by the CIA. It loaded its cargo for Nicaragua at an airfield in El Salvador which was built by the United States, the use of which Americans control. Its pilot was a former US Navy flier who had flown CIA missions. The US survivor is an ex-marine.

The US government denies any connection with the operation. It claims that this was a ``private'' operation that had been funded ``privately.'' This is the official cover story. Even if it were true it would not be plausible. You can't use a plane that has done work for the CIA in the past, man it with mercenaries who have flown missions for the CIA, load it from an airfield under CIA control, and expect the world to believe that this was a genuinely ``private'' operation.

A clandestine operation that ceases to be clandestine is a bungled operation. If the CIA can't do better than this, it ought to get out of the clandestine operations business. This was a case of evading the mandate of Congress in such a clumsy and amateurish fashion that Congress will be forced to do an investigation that is bound to embarrass both the CIA, for incompetence, and the Reagan administration for trying to evade a congressional mandate.

Then there is the old question, now re-raised by this episode, of the long-term usefulness to the US of such clandestine operations. The intent is to destabilize or overthrow a regime the US government finds distasteful. There have been two successful, and cheap, operations of this kind on the record. They have been classified as successful. But in the long term, were they?

The first was the overthrow of Iranian Prime Minister Muhammad Mossadegh in 1953. Ray Cline, former deputy director of the CIA, relates the story as follows:

``CIA mounted a modest effort under a skillful clandestine services officer who flew into Iran, hired enough street demonstrators to intimidate those working for Mossadegh, instructed Iranian military men loyal to the Shah how to take over the local radio station, and paved the way for the Shah's triumphal return.''

A year later President Arbenz Guzm'an of Guatemala expropriated the holdings of the US-owned United Fruit Company. This touched off a local political crisis. Quoting from Mr. Cline, ``A rival Guatemalan political leader, Castillo Armas, launched a desultory invasion of Guatemala supported by three P-47 fighter planes of World War II vintage flying from friendly Nicaraguan territory. The aircraft were provided by CIA and flown by soldier-of-fortune pilots recruited by CIA. There was not much fighting, but the P-47s created a lot of excitement, and support for Arbenz crumbled. A junta took over, made an accommodation with Castillo, and he became President in early July.''

Both operations succeeded but gave rise to ``romantic misconceptions as to the role and capabilities of the CIA'' which Mr. Cline later labeled as ``disastrous.'' It made it all seem too easy.

The overthrow of Mossadegh in Iran ushered in the reign of the Shah, which was followed by the Ayatollah Khomeini, who is far worse for the US than was the relatively weak Mossadegh.

In Guatemala the price for dumping the left-leaning Arbenz was a right-wing regime so brutal that its record of sudden disappearance and death has been a disgrace to the US-oriented community in Central America. Only within the year has a new regime done a moderate cleanup job in Guatemala.

Interfering in the internal affairs of other countries is a risky business with unpredictable consequences.