In the debate over the diplomatic agreement taking shape with Iran over its nuclear program, opponents led by Prime Minister Benjamin Netanyahu are deploying their ultimate rhetorical weapon – the Holocaust.

Netanyahu and his allies compare Iran to Nazi Germany and those who want to reach an agreement with Iran to control and contain its nuclear activities to appeasers who tried to buy off Adolf Hitler with concession after concession. Netanyahu has never directly said that President Barack Obama is today’s Neville Chamberlain – but the implication is there.

“Today, just like then, there are those who dismiss Iran’s extreme rhetoric as one that serves domestic purposes. Today, just like then, there are those who view Iran’s nuclear ambitions as the result of the natural will of a proud nation – a will that should be accepted,” Netanyahu said last year in a speech at Yad Vashem, the Holocaust memorial and museum in Jerusalem.

“And just like then, those who make such claims are deluding themselves. They are making an historic mistake,” he said.

In one 2006 speech, Netanyahu was even sharper. “It is 1938,” he said. “Iran is Germany, and it is about to arm itself with nuclear weapons.” The Israeli leader is likely to sound the same theme in his speech to Congress tomorrow. (If it was 1938 in 2006, then it is presumably 1944 by now).

Rabbi Shmuley Boteach, a failed Republican congressional candidate, used the same tactic when he took out a full-page advertisement in the New York Times over the weekend, singling out National Security Adviser Susan Rice for failing to stop the Rwanda genocide in 1994 when she was a NSC official. The ad, which was widely denounced by American-Jewish organizations, accused Rice of having a “blind eye for genocide,” showing her face alongside a row of skulls.

Others who have objected to the timing of Netanyahu’s speech or have supported the negotiations with Iran have been compared to the American-Jewish leaders during World War II who failed to demand that President Franklin D. Roosevelt order the bombing of railway lines leading to Auschwitz.

As the son of a Holocaust survivor who wrote a book about his experiences that was published by Yad Vashem, I certainly take the lessons of the Holocaust very seriously. As Jews, we’re all shaped in some respects by the Holocaust. It cannot be dismissed.

And I would also stipulate that the prospect of Iran with a nuclear bomb is terrifying. We are right to fear such a regime. But we do not serve our own interests best by basing our policies and our strategy on our emotions. As hard as it is to be calm in the face of a scary regime, we must look at the threat realistically and assess our options rationally.

One weakness in Netanyahu’s case is that he rarely outlines an alternative to diplomacy. Years of tough sanctions did not halt the Iranian nuclear program; there is little to suggest that ratcheting them up even more so will do so. If Netanyahu sees another way of dealing with the threat, he should tell us what it is.

There is a logical inconsistency in the Nazi parallel. As Netanyahu himself notes, there is no comparison to the defenseless European Jews of 1938 and the strong nuclear-armed Israel of today. Yes, Israel faces real security challenges and threats but we have come a long way since 1938 or even 1968 and we should acknowledge that.

Making Israel seem so puny and vulnerable against the potential Iranian threat in some ways negates the achievement of building the State of Israel and developing its military capability.

As Tzipi Livni has said, “We are not in the ghetto, and there is no place for Holocaust comparisons.”

Iran too is hardly Nazi Germany on the eve of World War II when it was by far the dominant military power in Europe, if not the world. It is far from being Israel’s equal in military capability. Iran is not being offered the chance to gobble up neighboring countries. It is being offered the chance over 10 to 15 years to rejoin the international community by scaling back its program and accepting strict and rigorous international supervision.

The Holocaust comparison also does an injustice to the Holocaust itself. As Israeli historian Yechiam Weitz wrote a few years back, “Netanyahu’s comparison did not transform the (Iranian) reactor in Qom into Auschwitz. It transformed Auschwitz into another reactor that might be dangerous.”

Netanyahu is hardly the first Israeli leader to invoke the Holocaust. Menachem Begin, in a letter to President Ronald Reagan in 1982, compared PLO leader Yasser Arafat hiding in besieged Beirut to Hitler in his bunker in Berlin. In 1967, before the Six Day War, Prime Minister Levi Eshkol privately compared Egyptian President Gamal Abdul Nasser to Hitler – though apparently not in public.

Ultimately, none of these parallels are useful. Nasser was Nasser, not Hitler. Arafat was Arafat. And Iran is not Nazi Germany. There’s certainly a lot of evil to go around. The Iranian threat should be taken extremely seriously. But it doesn’t serve us to label it or other dangerous threats we encounter another Holocaust

Let’s wait to see the deal if there is one and then debate it on its merits.