THE RIFT between the United States and Israel over Iran, which some are describing as the worst dispute between the two countries in 30 years, might be seen as yet another chapter in the consistently rocky and sometimes poisonous relations between President Obama and Israeli Prime Minister Benjamin Netanyahu. That would be a misreading. In reality, the argument reflects a more profound divergence of U.S. and Israeli national interests.

For the war-weary United States, a deal that halts Iran’s progress toward a nuclear weapon in exchange for partial sanctions relief, which the Obama administration hopes to conclude this week, would greatly reduce the possibility that the United States would be forced to take military action against Iran in the coming months. That risk has been growing because of Tehran’s installation of a new generation of centrifuges for uranium enrichment and because of the approaching completion of a reactor that could produce plutonium. If a long-term accord can be struck during a planned negotiating period of six months, the dangers of a new Middle East war and an Iranian bomb could be alleviated.

Israel, of course, also wishes to avoid war. But Israeli leaders have more to fear than do Americans from a bargain that leaves the bulk of the Iranian nuclear infrastructure in place, even temporarily. If no final settlement were reached, and the larger sanctions regime began to crumble — as the Israelis fear it would — Iran could be left with a nuclear breakout capacity as well as a revived economy. From Israel’s point of view, keeping sanctions in place until Iran agrees to a definitive compromise — or its regime buckles — looks like a safer bet.

But even a permanent settlement would be unattractive to Israel if it meant that the United States would step back from the regional conflict spawned by Iran’s decades-old effort to gain hegemony over the Middle East. Like Saudi Arabia and other Sunni Arab governments, Israel does not wish to be left alone to face Iranian aggression in Iraq, Syria and Lebanon or its terrorist activities across the region.

In the short run, there’s probably no way to bridge the divide between Jerusalem and Washington — unless Iran turns down the generous offer the United States and a coalition of five other nations have put forward. The administration has flatly rejected Mr. Netanyahu’s objections to an interim deal, and Congress appears unlikely to respond to Israeli lobbying for additional sanctions before the next Geneva meeting. Mr. Netanyahu would be wise to accept that an interim accord is likely to go forward without his agreement and let Iran take the blame if it does not.

Rather than argue in public, U.S. and Israeli officials should be working to forge a consensus on the terms of an acceptable final settlement with Iran. There, differences may not be as great: While Mr. Netanyahu campaigns for a permanent end to Iranian enrichment, a large reduction in Iran’s nuclear capacity, combined with more intrusive inspections, would leave Israel far more secure than at present. At the same time, the Obama administration ought to be assuring Israel and Arab allies that it will continue to reject Iran’s regional ambitions, respond to its aggressive acts and support the aspirations of Iranians for a democratic regime that respects human rights. With such understandings in place, the U.S.-Israeli argument would be manageable.