Natan Sachs in Foreign Policy:
Something has gone very wrong with Israel's posture on Iran's nuclear program. While Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak lead a confrontational approach — including dramatic interviews and speeches to U.S. audiences that have convinced many that Israel might soon strike Iran's nuclear facilities — the former heads of Israel's intelligence agencies have come out publicly against the government's position. First, Meir Dagan — who headed the Mossad until late 2010 and coordinated Israel's Iran policy — called an attack on Iran “the most foolish thing I've heard.” In April, Yuval Diskin — the previous head of the domestic intelligence service, the Shin Bet — voiced a scathing and personal critique of Netanyahu and Barak. Diskin questioned not only the leaders' policy, but also their very judgment and capacity to lead, warning against their “messianic” approach to Iran's nuclear program.
Given these differences, should the United States — and Iran — fear an Israeli strike more, or should they relax as Israel busies itself with internal arguments? Although it may be tempting to think that the Dagan-Diskin campaign lessens the chance of confrontation, in truth it raises two dire possibilities. First, if the former spy chiefs are correct about Netanyahu's and Barak's lack of judgment, this is hardly cause for comfort. If, however, Dagan and Diskin are mistaken and Israeli strategy is in fact calculated and sober, then undermining Israel's credibility — as they themselves have done — makes an Israeli strike more likely, not less. The less credible the Israeli threat, the more likely Iran is to try to call an Israeli bluff, and thus the more likely Israel is to try to back up its words with deeds.
More here.