A CRISIS is brewing in America’s relations with Israel. The American public—though strongly pro-Israel—seems either not to have noticed or not to care much.

In the coming days and months America and other world powers must decide whether a credible agreement can be reached to slow or halt Iran’s nuclear programme, in exchange for a lifting of crippling economic sanctions on the Islamic Republic. A final deal is months away at best. Israel has already launched a ferocious, pre-emptive verbal assault—aimed squarely at public opinion in America—after just two days of talks in Geneva about an interim agreement to slow Iran’s nuclear work for a few months, aimed at buying time for negotiations on a larger deal.

Israel’s prime minister, Binyamin Netanyahu, has not held back. In a speech to thousands of Jewish-Americans in Jerusalem on November 10th he more or less called the American president and his envoys naive to the point of imperilling Israel’s survival. Mr Netanyahu accused the negotiators in Geneva, including John Kerry, the secretary of state, of proposing “a bad and dangerous deal” that would start to unravel sanctions even as Iran retained its capacity to enrich enough fissile material to menace Israel’s survival. America would be next, once Iran perfected long-range missiles, he warned. “Coming to a theatre near you. Do you want that?” he growled. “Well, do something about it.”

Mr Kerry retorted that Barack Obama’s government understands where America’s interests and those of its allies such as Israel lie. He snapped: “We are not blind, and I don’t think we’re stupid.” The ground might seem set for a familiar American political showdown in which Republicans denounce Democrats for coddling America’s enemies while cold-shouldering its allies.

Yet, with a few exceptions, this is not happening. Instead some big-name Republicans, including likely contenders for the White House, have dodged invitations to whack the president with the cudgel proffered by Mr Netanyahu. “When guys like me start to shoot off on opinions about this kind of stuff, it’s really ill-advised,” Chris Christie told an interviewer asking about Iran, preferring to discuss his thumping re-election as governor of New Jersey. At the libertarian end of the 2016 Republican field, Senator Rand Paul of Kentucky was careful to praise Israel during a flag-waving speech to military cadets on November 12th, intended to soothe conservatives who think him flaky on national security. “One thing you can know for sure is, you will never see an Israeli burning the American flag,” Mr Paul enthused, bumper-stickerishly. He did not mention Iran or its nuclear ambitions.

One explanation is that Americans are weary of war and even of suggestions that they should fix crises far from home. Iran may give foreign-policy wonks the vapours, but American voters feel they have heard a lot of cry-wolf warnings about weapons of mass destruction in recent years, so they are taking a break from wolf-hunting. Bob Corker of Tennessee, the senior Republican on the Senate Foreign Relations Committee, worries that Mr Obama has a habit of “dealing away America’s leverage”. But Senator Corker concedes that in the days after Mr Kerry’s abortive Geneva talks on Iranian nukes, his office did not receive a single call about Iran from a constituent. In contrast, when a congressional vote on bombing Syria loomed in September, after the Assad regime used chemical weapons, his staff were “inundated” with calls opposing American military action.

The intense partisanship of modern politics further complicates any attempt by outsiders to rally American support. It is not that Americans are turning anti-Israeli. A 2013 Gallup poll found 64% of them sympathetic to Israel in its dispute with the Palestinians, matching a previous all-time high. But that headline number conceals important nuances. Republican enthusiasm for Israel tracks events that affect America, with big spikes around the September 11th attacks and both Gulf wars. Democrats are markedly more ambivalent about Israel. Most Jewish-Americans vote Democratic. And they are divided in their views of Israel, too. A recent Pew poll of Jewish-American voters found them sceptical about the Israeli government’s commitment to making peace with the Palestinians (fewer than one in five thinks West Bank settlement-building makes Israel more secure). On many measures, white evangelical Protestants are a more reliably pro-Israel voter bloc (possibly because white evangelicals are twice as likely as American Jews to believe that God gave Israel to the Jews).

The Israeli lobby loses leverage

To those who brood, darkly, about Israel’s influence in American politics, the bogeyman of choice has long been the American Israel Public Affairs Committee (AIPAC), a hawkish lobby group. AIPAC’s friends in Congress, notably Robert Menendez, the Democratic chairman of the Senate Foreign Relations Committee, have suggested that new sanctions would strengthen America’s hand with Iran. Congress has the power to approve new Iran sanctions, or even to curb Mr Obama’s ability to waive sanctions now in place. If fresh Iran sanctions were allowed to come to a Senate vote, they would pass easily (the Republican-controlled House of Representatives has passed its own fearsome sanctions but cannot make laws alone). That leaves Democratic leaders of the Senate with a dilemma. They do not wish to embarrass their president. But senators distrust Iran intensely, and are not convinced that Mr Obama will insist on a robust deal, either. AIPAC will need to tread carefully—a core tenet of Israeli diplomacy is maintaining bipartisan support in America.

The Iran crisis has sharpened old differences between Mr Netanyahu and Mr Obama. But with the American public wary of foreign entanglements, Congress is a weaker-than-usual ally. In the struggle with Iran, Mr Netanyahu is stuck with Mr Obama. They may disagree profoundly on tactics, but there is little support in America for what Israel’s premier has in mind.