The Hebrew word for nuclear opacity or ambiguity is amimut, which Avner Cohen believes to be “Israel’s original contribution to the nuclear age.” Avner has written two books on Israel’s bomb. His latest, The Worst-Kept Secret: Israel’s Bargain with the Bomb (2010) acknowledges the prior utility of amimut, while highlighting its corrosive effects for “democratic values at home and with norms of transparency in the international arena.”

Avner argues that amimut provides a “helpful fiction that serves international security and stability” for Israel, the United States, the Middle East, and the Nonproliferation Treaty regime. But in the event of a “nuclear Iran” — which may well be in Tehran’s interest to define suggestively — Avner concludes that “Israel would have to declare its capability” in order to reinforce deterrence. Another strong reason for dispensing with ambiguity, in Avner’s view, is that, “By accepting amimut, Israelis have effectively deprived themselves of one of their most democratic rights.” There’s more: “The principal drawback of amimut… is that it leaves too much ambiguity as to who is in charge.” The bottom line: “Israel’s insistence on the exceptionalism of amimut is not only parochial and anachronistic; it is wrong for both Israel and the world.”

I liked Avner’s book in draft, and I like the final product even more. No one writes in greater detail or with more authority on Israel’s nuclear program than Avner Cohen. It seems to me, however, that there are serious weaknesses in his arguments.

There is, to begin with, little ambiguity left about Israel’s possession of nuclear weapons. Consequently, it is hard to argue that nuclear deterrence will be greatly reinforced by slips of the tongue, official declarations by Israeli Prime Ministers, or other means. By going public, Israeli authorities would instead make it even harder for others to leverage Iran and easier to isolate Israel, while adding fuel to the upcoming, combustible conference on a Middle East zone free of weapons of mass destruction.

Following Avner’s advice would be likely, in my view, to weaken rather than strengthen Israeli nuclear deterrence and further unhinge regional stability, which is already reeling from popular revolts in the Arab world against rulers who have stayed in power for far too long. Israel’s nuclear deterrence without the usual public trappings is, indeed, exceptional. Iran may be following as far down this path as internal cost/benefit analyses suggest. It is doubtful, however, that greater clarity about Israel’s nuclear capabilities will affect Tehran’s choices. Instead, greater clarity about Israel’s nuclear capabilities is likely to increase Tehran’s freedom of maneuver. Avner makes a much stronger case arguing for normal democratic discourse about nuclear matters – but not strong enough, in my view, to override the weakness of his case for gradually dismantling amimut.