By Dan Williams
JERUSALEM (Reuters) - He may be ready to brave Iranian air defenses, retaliatory missiles and Western diplomatic blowback in tackling Tehran's nuclear program, but Israeli Prime Minister Benjamin Netanyahu will find it hard to fly past flak from his own senior staff.
Remarks by recently retired security chiefs and the current military commander questioning the views of Netanyahu and Defence Minister Ehud Barak on Iran have opened a rare rift in a Jewish state that usually puts up a united front against regional enemies.
Yuval Diskin, who as former Shin Bet domestic intelligence chief was effectively in charge of vetting government officials, on Friday deemed Netanyahu and Barak "messianic" and unfit for war.
If the Netanyahu government was ever serious about carrying out a long-threatened, last-ditch and tactically thorny assault on Iran's nuclear sites against the misgivings of many Israelis and foreign allies like the United States, the criticism from Diskin and others may have tipped the scales against.
The right-wing premier describes a future Iranian bomb as a second Holocaust-in-the-making, to be stopped at all costs.
But that case may be tougher to make in the face of derision from men he once trusted to fend off immediate threats like suicide bombers, guerrilla rockets and armed infiltrators.
"They genuinely disagree and are trying to signal the Israeli public, knowing that they retain credibility," said Dennis Ross, a former Middle East adviser to U.S. President Barack Obama, in reference to Diskin and Mossad ex-spymaster Meir Dagan, another detractor of Netanyahu and Barak.
"They are raising the costs domestically to the Netanyahu government of acting."
A second-term prime minister with solid approval ratings, Netanyahu is mindful of public opinion, especially with the prospect of a scheduled 2013 election being brought forward to within months.
Arguments by Dagan and Diskin that an Iran war could spill out of control, with knock-on reprisals from Syria and Islamist militants in Lebanon and Gaza, resonate with Israelis who demanded commissions of inquiry over the costs of far more contained border conflicts in 1982 and 2006.
"With this kind of a prospect, many Israelis, regardless of political stripe, are reminded of past adventures which proved to be misadventures," said Amotz Asa-El, a fellow with the Shalom Hartman Institute, a liberal Jerusalem think-tank.
"REVOLT OF THE DEFENDERS"
Israeli officials accused Dagan and Diskin of using Iran to settle scores with Netanyahu and Barak after being denied extended tenures, or to launch political careers of their own.
But Israel's current top general, Benny Gantz, also clashed with government messaging last week by describing Iran as "very rational" and unlikely to develop an atom bomb.
"We are witnessing a very deep fissure between the security establishment and the political level (which is) quite unprecedented," said another U.S. ex-official, who asked not to be named. He dubbed it a "revolt of the defenders".
Such American apprehension is dreaded by Israel, which looks to its guardian ally to spearhead an international sanctions drive designed to curb Iran's disputed uranium enrichment.
Netanyahu aides say those negotiations can succeed only if the world thinks he is poised to attack, despite all the risks, and that this impression is dented by naysayers who can claim knowledge of Israel's secret capabilities and debates.
"If you are against Israel taking military action, the worst thing you can do is undermine the credibility of that option," one senior official said, suggesting that eroding the diplomatic pressure on Tehran risked making war Israel's only resort.
The official, who spoke on condition of anonymity given the sensitivity of the issue, said Israel worried that remarks like Diskin's could dilute international demands that the Iranians stop all uranium enrichment, a program that has bomb-making potential though Tehran insists it is for peaceful energy only.
"We are already seeing signs of capitulation" to Iran in the talks due to resume in Baghdad on May 23, the official said.
Such disclosures suggest that Israel's war footing may have been as much bluff as true intent. As Diskin put it, "barking dogs don't bite".
Indeed, during his accrued six years in top office, Netanyahu has not embarked on major military offensives - leading some critics to describe him as gun-shy.
Then again, Netanyahu would be loath to see Iran go nuclear on his watch, and has differed with military experts in the past. He warned against unilateral withdrawals from occupied Lebanese and Palestinian territories and appeared to have been vindicated when those evacuations hardened Islamist hostility to Israel.
Netanyahu's ideological forbear, Prime Minister Menachem Begin, beat back skepticism from some of his advisers to order the 1981 bombing of the nuclear reactor in Saddam Hussein's Iraq. The mission was a success, with world outcry later giving way to gratitude.
David Ivry, who oversaw the raid as then-Israeli air force chief, said Netanyahu and Barak might see the required cabinet approval for a similar Iran strike as enough to test fate.
"In the end, history is the judge," Ivry said.
(Editing by Jeffrey Heller and Mark Heinrich)