The retirement of Yehiel Horev last week from the post of Security Chief for the defense establishment drew public attention on the man - a 44-year-old veteran civil servant, who spent nearly half his life in security - but very little on the organization he headed.

This is in and of itself an indirect achievement of the man who for two decades was the main "ambiguator" of Israel - the chief of staff of ambiguity. They only spoke of him, so much so that they forgot to ask whether that mysterious agency he headed was still necessary, an agency hidden in the shadows of the lower floors of the tower in the Defense Ministry's compound, which employs hundreds at the headquarters, in various branches, and in industry.

The security organization, known by its Hebrew acronym as MALMAB, emerged in 1975 out of the Bureau for Science Relations, an agency whose purpose was to protect the secrets of the Dimona nuclear reactor. Another one of its missions was to acquire, clandestinely, know-how and materials that could be used for Israel's strategic infrastructure.

The Bureau of Science Relations had been in operation since the late 1950s, and its path was as twisted as it was based on short-cuts. Defense Minister Shimon Peres, its founder and first sponsor, split the bureau in order to create a new position, at the MALMAB, for his crony, Haim Carmon.

When the Jonathan Pollard scandal erupted in a great big bang, the Americans demanded the head of the chief of the Bureau of Science Relations, Rafi Eitan, and the dissolution of the agency. Eitan was forced to resign, as was the air force officer, Aviam Sela - who recruited Pollard and was one of his handlers - but the dissolution of the agency did not really happen. The Bureau was absorbed by the MALMAB. Carmon was elevated to another position, with its own acronym (MAKSAM), which incorporated External Relations, Defense Assistance and the MALMAB. In practice, Horev - Carmon's successor at MALMAB - answered to the director general of the Defense Ministry. In particularly sensitive matters, he spoke directly with the defense minister and the prime minister.

The way Horev began foretold the way he would end. He, too, along with Defense Ministry Director General Amos Yaron, fell victim to American pressure in the matter of Israel's security relations with China. Yaron and Horev are convinced that they were wronged. What began as an honest misunderstanding exploded into a struggle over prestige among people who are not willing to admit mistakes. The Pentagon's opposition to Horev's appointment as director general of the Defense Ministry did not prevent Kathleen Weston, director of the Defense Security Service, the counterpart (partly) to MALMAB, answerable to the Under Secretary of Defense for Intelligence, to host him with professional respect during a working visit that was also a farewell.

Horev dealt with securing information and facilities, in procurement, and contacts with certain countries. But his supreme mission remained the preservation of nuclear ambiguity - that original Israeli stance, at once modest and tempting, denying but not overly so, hinting at its ability to keep enemy attacks at bay but claiming not to be able to, so it is not pressured by its allies.

In what has been a major marketing success, Horev was depicted as a stubborn prosecutor of anyone threatening to crack nuclear ambiguity: Mordechai Vanunu, Brigadier General Yitzhak Ya'akov, researchers of Israel's nuclear history. He marked his belt with non-nuclear kills: Marcus Klingberg (Horev believes that had it not been for him there would have been a second spy of Israel's biological programs in the service of the KGB); Nachum Manbar; and the Arrow ABM system developer, Dov Raviv.

It is arguable whether the right place for the MALMAB is at the Defense Ministry. If the Atomic Energy Committee was housed in the Prime Minister's Office, along with the Mossad and the Shin Bet, then maybe MALMAB should also be there. This is an organizational issue, similar to the dispute over the work of Nativ [a body acting as a liaison with Jewry behind the Iron Curtain] independently from the Mossad.

The essential question is over nuclear policy. So long as Israel sticks to its policy of ambiguity, it requires a guard to protect it. It is necessary for this guard to be closely supervised, so it will not run amok and persecute, and it is desirable for a more frequent change of the figure at its top; but whoever is in favor of Dimona cannot be against MALMAB.