Never has it been more difficult for Prime Minister Benjamin Netanyahu of Israel to convince the world that, as he put it in 2006: “It’s 1938. Iran is Germany.” He tried again at the United Nations this week. In a speech that strained for effect, he likened Iran to a 20th-century “radical regime” of “awesome power.” That would be the Third Reich.

Among those who question this approach is David Harris, the executive director of the American Jewish Committee. Referring to the new Iranian president, Hassan Rouhani, he wrote in the Israeli daily Haaretz that, “Simply implying, for instance, that anyone who sits down with Rouhani is a modern-day Neville Chamberlain or Édouard Daladier won’t do the trick. To the contrary, it will only give offense and alienate.”When Netanyahu’s staunchest supporters — the leaders of the American Jewish community — question his approach to Iran, the Israeli prime minister needs to stop calling Rouhani “a wolf in sheep’s clothing,” his favored epithet, and start worrying about crying wolf.

It is not just that the world has now heard from Netanyahu of the imminent danger of a nuclear-armed Iran for a very long time. It is not just that Israel has set countless “red lines” that proved permeable. It is not just that the Islamic Republic has been an island of stability compared to its neighbors Syria, Iraq and Afghanistan. It is not just that, as Rouhani’s election shows, Iran is no Nazi-like totalitarian state with a single authority but an authoritarian regime subject to liberalizing and repressive waves.

No, Netanyahu’s credibility issue is rooted in the distorted priorities evident in a speech that was Iran-heavy and Palestine-lite. The real challenge to Israel as a Jewish and democratic nation is the failure to achieve a two-state peace with the Palestinians and the prolongation of a West Bank occupation that leaves Israel overseeing millions of disenfranchised Palestinians. A recent Pew Research Center survey found that only 17 percent of American Jews think that the continued building of West Bank settlements is helpful to Israel’s security.

Iran has long been an effective distraction from the core dilemma of the Jewish state: Palestine. But global impatience with this diversionary strategy is running high.

Iran has much to answer for. Rouhani’s “Iran poses absolutely no threat to the world or the region” is a preposterous statement. It has hidden aspects of its enrichment program. It has taken American and Israeli lives and attacked U.S. interests, through the Revolutionary Guards, Hezbollah and other arms of its security apparatus. It has placed odious Israel hatred and America-as-Satan at the core of its revolutionary ideology. President Obama is right to demand transparent, verifiable action for any deal.

What Iran has not done is make a bomb or even, in the view of Western intelligence services, decide to do so. Rouhani’s call for “time-bound” negotiations on a nuclear deal should therefore garner full Western engagement without Israel acting as a spoiler.

It is not in Israel’s interest to be a spoiler. Limited, highly monitored Iranian enrichment — accepted in principle by Obama but rejected by Netanyahu — is a far better outcome for Israel than going to war with Tehran. But, of course, any deal with Iran would also have to involve a change in the Iranian-American relationship. Israel does not believe that is in its interest, hence some of the bluster.

Netanyahu should cut the bluster and shift focus, instead, to Israeli-Palestinian talks. In the past, he has been able to turn to Congress and leading American Jewish groups for support when he felt isolated. During Obama’s first term, when tensions were high between the two leaders, he got 29 standing ovations in Congress. But today Harris’s questioning of Israel’s approach is not the only sign of shifts.

It was striking that the Obama administration sent Vice President Joe Biden to address the growing J Street organization, which is pro-Israel but not uncritical of Israel, at its annual conference in Washington this week. It is also striking that Louis Susman, who is close to Secretary of State John Kerry and was the U.S. ambassador to Britain, has joined the J Street board. I am told he may soon be joined on the board by Samuel Kaplan, the former U.S. ambassador to Morocco.

Harris has agreed to debate Jeremy Ben-Ami, the executive director of J Street, in New York later this year. In the past, leaders of major Jewish organizations tended to shun J Street, as has the powerful American Israel Public Affairs Committee.

What all this means is that if Israeli-Palestinian peace negotiations get close to a tipping point in the coming months, there will, for the first time, be an organized, well-funded American Jewish constituency committed to a two-state outcome trying to push Netanyahu over the line, rather than comfort him in rejection.

That is significant. Netanyahu should adjust to changed circumstances rather than rehearse tired Iranian tropes.