The United States should offer Israel a “nuclear guarantee” before signing an agreement with Iran about its rogue nuclear program, a former top American foreign policy official suggested Tuesday.

Martin Indyk, a former American envoy to Israel and mediator in Israeli-Palestinian peace talks, said such a deal would serve to assuage Jerusalem’s fear about Tehran violating the deal and subsequently dashing toward a bomb.

“The United States can afford to have Iran as a near-threshold nuclear power. And Israel is saying it can’t. And that’s related to the very different security circumstances of the US and Israel,” Indyk said during a panel discussion at the Institute for National Security Studies’ annual conference in Tel Aviv. “Instead of having an argument about that, the United States should enter immediately into discussions with Israel about a nuclear guarantee for Israel.”

Such an arrangement would take the form of a bilateral treaty, Indyk explained.

“It would require legislation and I believe it would pass pretty much unanimously,” he said.

The guarantee would commit the US to take some sort of action should Iran cross a certain threshold, though Indyk did not say exactly what the specific contours of such a deal would take.

Also known as nuclear umbrellas, guarantees are often used by nuclear-states as a promise to protect smaller allies.

Israel first demanded a nuclear guarantee during the Camp David peace talks 15 years ago, said Indyk, who at the time served as Washington’s ambassador to Israel.

Then-prime minister Ehud Barak asked US president Bill Clinton to provide such a guarantee in the framework of a potential peace agreement with the Palestinians.

Clinton agreed, according to Indyk, who served as the president’s special assistant and as senior director for Near East affairs at the National Security Council.

The treaty he is proposing now would be “a different kind of deal, but it might go a considerable distance toward calming Israeli concerns about the consequences of an Iranian reneging on the commitments,” Indyk said.

Itamar Rabinovich, a former Israeli ambassador to Washington, who also participated in the panel, said Jerusalem should view such a guarantee carefully, since any agreement with the US would surely preclude any Israeli military action against Iran’s nuclear program.

“Israel’s freedom of action would be limited. You cannot ask for an automatic American guarantee and then go act on your own,” he said.

Indyk in his remarks also criticized Prime Minister Benjamin Netanyahu’s controversial insistence to address US Congress later this month on the Iranian issue, indicating that it turned support for Israel’s position into a partisan issue.

“One has to think about what exactly is going to be achieved by this speech,” said Indyk, who served as the US administration’s special envoy for the last round of Israeli-Palestinian peace talks. “Is it really going to turn around the minds of the president of the United States and his negotiators? Will they suddenly wake up and say, ‘Oh we’re negotiating a bad deal here, silly us, we’ll change our minds’? Will it convince a veto-proof majority in the Senate that they should act in a way to sink the deal?”

US President Barack Obama has vowed to veto any bill that would call for additional sanctions on Iran as long as the nuclear negotiations are ongoing.

Netanyahu’s speech might have been able to influence American lawmakers if it had been arranged in a way that would create bipartisan support for Israel’s understandable concern about a potential nuclear deal with Iran, Indyk posited.

“But the Republicans don’t have 60 votes in the Senate. They don’t have the votes without the Democrats to do anything. Without those votes, the speech is not going to be able to achieve anything,” he said.

But the way in which speech was handled — with Speaker of the House John Boehner inviting Netanyahu behind the administration’s back — “put the Democrats, who might otherwise cheer the prime minister on the substance of the matter, in an impossible situation, where they have to choose between the prime minister of Israel and the president of the United States,” Indyk said. “And that’s an untenable position.”

Israel’s enemies are currently “celebrating,” according to Indyk, “because they love to see a split between the United States and Israel. It’s a real problem.”

The current tensions between Washington and Jerusalem are dangerous for Israel but also for the US and its influence in the region, said Indyk, who currently serves as vice president and director of the Brooking Institute’s Foreign Policy Program.

The current US ambassador to Israel, who also addressed the conference, downplayed the tension between the two governments.

“Our cooperation and consultation with Israel on this shared goal [of preventing a nuclear-armed Iran] will continue, even at moments when we may disagree on one or another aspect of the approach,” Dan Shapiro said.

Rebutting reports that the US has ceased to update Jerusalem on the current negotiations with Iran, Shapiro said senior US officials dealing with the issue have met and continue to meet with their Israeli counterparts.