Obama now faces the most critical moment in his presidency. He speaks to the United Nations this morning, and the speech and whatever follows perhaps will initiate a renewed negotiation with Iran over the latter’s nuclear program. The stakes in the negotiation may be as dramatic as war or peace, and their outcome will likely set the trajectory for America’s Mideast policy for at least the next decade.

Since his 2008 inauguration, Obama has tried to split the difference between his liberal internationalist and realist supporters and hawkish pro-Israel elements. That meant he backed off on pushing Israel to stop growing its West Bank settlements, while also pouring cold water on Israeli plans for a preemptive strike on Iran. But now all the issues which could be kicked down the road are approaching a boiling point. Iran’s newly elected leaders are signaling in every possible way that they want relief from sanctions and responsible relations with the West. In return they are willing to accept restrictions and oversight on their nuclear program, ensuring it will not produce nuclear weapons. Israel, which has called the tune on American relations with the Mideast for decades, is in a sort of panic at this prospect, fearing that Obama and the West will start a detente process with Iran, leading to normal and mutually beneficial relations. Israel is like Taiwan in 1971, but with vastly more cultural and economic power within the U.S. than Chiang Kai-shek’s nationalist regime. Bill Kristol and the Weekly Standard are claiming, without reaching a large audience thus far, that Iran’s newly elected president Rouhani represents a Hitlerian threat to the West, and more, that Israel is the leader of the West. Curiously, this bizarre claim was made at the very moment Israeli military forces were abusing European diplomats attempting to deliver aid to Arabs being dispossessed by Israel’s ongoing ethnic cleansing operations in the West Bank. So yes, Israel is certainly the very model of Western leadership, if that leadership consists of ethnic cleansing and abuse of those Western diplomats who try, however ineffectually, to oppose it.

But Kristol has allies, even in the Obama administration. Gary Samore, who was a leading nuclear negotiator in the administration, recently signed on as president to an anti-Iran lobbying group which distinguished itself by trying to deny New York City hotel accommodations to President Rouhani and his delegation. As telling as Samore’s role in setting American policy is the letter released today by Senators John McCain and Charles Schumer, calling for the United States to adopt a negotiation strategy that is all take and no give, and which has no chance of success. It’s not surprising about McCain–he’s a perpetual warmonger in his dotage. But Schumer is key Democrat, albeit one who styles himself as Israel’s “guardian”. And Israel wants the United States to go to war against Iran, or at least wants Washington to ensure in perpetuity not only that Israel retains a nuclear weapons monopoly in the Mideast, but a monopoly as well on uranium enrichment and knowledge of nuclear fuel cycle. Margaret Thatcher once said Israel was mistaken to insist on rights for itself which it denied to other people. She was speaking of Palestinian aspirations for statehood at the time, but her words, essentially the Golden Rule applied to diplomacy, could well apply to Israeli nuclear policy.

Whether Obama has the will and political strength to resist this pressure, whether he can explore soberly whether the United States might benefit from regular relations with a large, technologically advanced, and democratically inclined Muslim country, will be the greatest test of his presidency.