Israeli leaders say they are willing to wait as President Barack Obama plays out his strategy of negotiating with Iran while threatening stronger sanctions if talks fail. They say last week's disclosure of a previously secret nuclear enrichment plant under construction in Iran strengthened the case for harsh international measures. And while they remain skeptical that anything short of force will derail Iran's nuclear plans, the Israelis are careful to emphasize that attacking its reactors and missile sites is an option the Obama administration, not just Israel, holds in reserve. 'The foundations have been laid for halting Iran by establishing a broad international coalition led by the United States,' Deputy Foreign Minister Danny Ayalon said this week. 'The tools the United States has at its disposal are much stronger, much more serious.' Iran says its nuclear program is for civilian energy production; Israel and many in the West are convinced it is aimed at developing nuclear weapons. At Thursday's meeting in Geneva, the United States and its allies will demand that Iran open the enrichment facility to international inspectors and provide unfettered access to related documents and scientists involved in its construction, U.S. officials say. Britain, China, France, Germany and Russia also are to take part in the meeting. Israel has coupled support for the diplomatic effort with appeals to the participants to prepare maximum sanctions. In televised interviews last week, Prime Minister Benjamin Netanyahu said the Iranian government is so unpopular at home that 'crippling sanctions,' including an embargo on gasoline shipments, could undermine it further. 'The application of this pressure might do the job,' Netanyahu said. 'The sooner we do it, the sooner we'll find out and the less will be the need to take stronger action.' Israel, itself an undeclared nuclear power, has voiced alarm over calls by Iran's president for its demise. Israel closely monitors its arch-enemy's nuclear and missile development while building up its own strike capabilities and missile defenses. Israel's leaders undoubtedly knew of the clandestine facility well before its disclosure last week, Israeli analysts said, and had factored it into planning for a possible pre-emptive strike. Officials and analysts in Israel acknowledge that an attack on Iran carries huge risks and might fail to deter it from building a bomb. Yet Israel's record of successful pre-emptive strikes -- on a partially built reactor in Iraq in 1981 and what U.S. officials said was a nearly complete reactor in Syria in 2007 -- has bolstered arguments here for a limited attack on Iran's widely scattered facilities. Israel's warnings had grown over the past year along with its doubts that Obama was willing to confront Iran. But his decision last week, joined by Britain and France, to use the hidden enrichment plant as leverage against Iran cast the American leader in a new light in Israel. 'American policy on the entire Iranian issue has undergone ... significant changes since President Obama took office,' said Michael B. Oren, Israel's ambassador to the United States. 'At the beginning, it was seen as an Israeli problem.... Somewhere around the summer, the U.S. administration began regarding Iran as a world problem and as an American one. These changes make it somewhat easier for us.' (Begin optional trim) Ephraim Halevy, a former head of Israel's foreign intelligence service, said Obama still faces a daunting challenge in facing down Iran. 'But now he has everyone behind him,' Halevy said. 'It's an entirely different situation from what he had a week ago.' In part to bury the notion that Iran threatens no one but Israel, Israeli officials have said little in public about the Iranian plant and issued no formal reaction to the Islamic Republic's test-firing Monday of missiles with sufficient range to strike the Jewish state. Halevy said there's a good chance this week's talks will succeed in deterring Iran because its leaders feel cornered. 'Israel should allow this dialogue to take place quietly and seriously, with all options continuing to exist in the background, of course, in case it fails,' he said. (End optional trim) Less optimistic analysts believe Iran is so close to nuclear weapons capacity that it would be willing to risk provoking the most punishing sanctions. They say the diplomatic effort could lead by next spring to two outcomes difficult for Israel: One is a deal allowing Iran to continue enriching uranium at low levels for energy purposes, under an international supervision regime Israel regards as too weak to stop the development of a weapons program. If Obama and other world leaders applaud such a step, analysts say, Israel's hands would be tied. The other outcome, a failure by world leaders to agree on sanctions that dissuade Iran, would force Israel to decide between living with a nuclear-armed Iran and attacking it. U.S. officials have tried so far to discourage a unilateral Israeli strike, and many analysts doubt the Israelis would launch one without at least a quiet nod from Washington. The risks for Israel would include blame for any Iranian retaliation against American troops in Iraq as well as deadly strikes on its own people. 