By Dan Williams and John Irish
JERUSALEM/PARIS (Reuters) - Prime Minister Benjamin Netanyahu has begun to signal that Israel could resign itself to an Iranian nuclear deal that would leave its enemy with some uranium enrichment capability, a compromise he has long opposed.
The shift seems surprising given Netanyahu's contentious speech to the U.S. Congress earlier this month in which he argued against world powers letting Tehran keep thousands of uranium centrifuges and remain on possible course to a bomb.
But faced with Western impatience and White House wrath over the calls to avoid a "very bad deal" - while offering no detailed alternative of his own - Netanyahu and his envoys are now engaging with negotiators on the small print of what Israel hopes will be a better agreement.
Almost lost in the prime minister's March 3 denunciations in Congress was a line urging U.S. President Barack Obama to seek a "better deal" that "Israel and its neighbors may not like, but with which we could live, literally".
Pressed to elaborate, Netanyahu, who won a fourth term in Israel's March 17 election, told MSNBC in an interview two days later that Israel and like-minded Arab states might accede to Iran not giving up of all its uranium centrifuges.
Iran insists its nuclear drive is peaceful and wants to keep at least 9,000 of the centrifuges, which are used to process uranium to energy-yielding purity but could potentially make warhead fuel too.
World powers have spoken of allowing Iran to have 6,500 centrifuges, a number they assess would slow the "break out" period Iran would need to build a bomb to a year - time enough to intervene.
The Israelis, who are not a party to the talks but have been heard out in Western capitals due to their fears of a nuclear-armed Iran and their threats - now looking increasingly hollow - to launch a unilateral war of last-resort, have made clear they want their foe left with much less.
But they have not presented a comprehensive counter-proposal, a reticence that one Israeli nuclear official told Reuters was designed to avoid providing a "bottom line" that negotiators might try to stretch in their talks with Iran.
Instead, officials say, Israel has been challenging Western powers on specific details of a deal, such as strong technical safeguards and extending the breakout time.
"We think to leave Iran one year from the bomb or 1.5 years is too dangerous because sooner or later they will dash to the bomb," Strategic Affairs Minister Yuval Steinitz, Netanyahu's point-man on Iran, told Reuters this week during a visit to Europe, where he conferred with French and British counterparts.
DETAILS IN FOCUS
Israel, Steinitz said, preferred a 2- to 3-year breakout time - a disclosure in itself reflecting the recalibration by Netanyahu, whose advisers previously said that Iran, if stripped of all nuclear projects, could reconstitute them in five years.
Steinitz argued the one-year breakout could apply even if Iran were left with just 3,000 to 4,000 centrifuges, given its capacity, known by the rubric "research and development", to improve their performance and manufacture more at short notice.
"We claim that if Iran is permitted to preserve 6,000 centrifuges the breakout time is not 12 months but around nine to 10 months, even with zero (uranium) stockpiles," Steinitz said, urging world powers to insist on technological curbs.
"Although we are against a deal in general, we are also focusing on specific items within this wrong deal," he said, adding that Iran should also be compelled to come clean on allegations it had conducted secret nuclear weaponization tests.
"R&D is the most important topic on the table."
A European diplomat confirmed this was now the Israelis' focus, saying that although they "are clearly not fans of the one-year (breakout) they are principally concerned by research and development and want the most restrictions possible on it. The message is simple: stop all enrichment possibilities."
"They are very conservative on each parameter and pushing for the most conservative and restrictive measures, but they appear to be more flexible than what they originally wanted."
A U.S. diplomat, who also spoke to Reuters on condition of anonymity, said it was still unclear how many Iranian centrifuges might get Israel's grudging assent.
"In private they have been talking about small numbers but the devil is in the details. What's small to us is not small to them," the U.S. diplomat said.
Israeli hopes of seeing Iran denied any refined uranium capacity were dashed by its November 2013 interim deal with world powers, which envisaged a final agreement permitting it a "mutually defined" and "peaceful" enrichment program.
Negotiators want to agree the deal by June 30, and an outline by next week, despite disputes among Western delegates. Iran on Wednesday said any agreement must involve the immediate lifting of sanctions on it, a demand rejected by the West.
At loggerheads with a Washington weary of Middle East wars, Netanyahu has not played up past threats to attack Iran. Asked how Israel might respond if a nuclear deal that it opposes goes through, Steinitz said: "I don't know."
Another senior Israeli official was circumspect, saying: "Would Bibi (Netanhayu) go to war over 5,000 centrifuges? I'm not so sure."
(Additional reporting by Lou Charbonneau at the United Nations; writing by Dan Williams; editing by Anna Willard)