For years I have heard various individuals and organizations claim that if they had been around in the 1930s-40s, the Holocaust might have been prevented. Thankfully, they say, because they are here now, nothing like that can ever happen again. On a number of occasions I have seen reasons to doubt these claims and today’s debate on Iran may be another.

One problem has been Prime Minister Benjamin Netanyahu’s persistent warning that Iran poses an existential threat to Israel. In the past I wrote that he had begun to sound like the little boy who cried wolf. He repeated this mantra so often that no one outside Israel listens to him, except perhaps some members of the U.S. Congress. Still, the fact that he is ignored does not mean Netanyahu is wrong.

Iran’s leaders have consistently threatened to destroy Israel and, if they had the means, Israelis would be justifiably concerned. Some argue Iran would never attack Israel because of Israel’s second strike capability, which could wipe Iran off the map, and the likelihood the United States would also respond (though Israelis don’t trust Obama), but no Israeli prime minister — and the opposition Zionist Union leaders just made this clear — could afford to risk the future of the Jewish State by hoping the Iranians don’t mean what they say.

If Iran poses an existential threat, Israel must act. Certainly there are obstacles. An operation to destroy Iran’s nuclear infrastructure, if only for a few years, appears to be a daunting military challenge. The consequences of such an attack could also be dire depending on how Iran and other Muslims and Arabs react. Netanyahu reportedly wanted to launch an attack a few years ago and was overruled by his own military advisers. He also must weigh the possible reaction of the United States and other Western allies. Would the United States obstruct an Israeli attack to protect what President Obama sees as America’s interests? And, given Obama’s attitude toward Israel, can Netanyahu afford to jeopardize the future of U.S.-Israel relations — at least for the remainder of Obama’s term?

Israel has made no secret (nor have the Saudis and other Arabs for that matter) that it would prefer to see the United States act unilaterally or with a coalition of forces. The problem is that few people in the Middle East (except maybe terrorists targeted by drones) fear this president. Obama sent a disturbing message to America’s allies when he ignored Syria crossing his red line by using chemical weapons and thereby increased distrust that he will act differently if Iran used nuclear weapons. The general view is that he will do anything to avoid another military engagement and that he believes he can cement his legacy by reaching an agreement with Iran, no matter how dangerous others consider that deal to be.

Obama asserts the agreement does not rely on trust but verification. The problem is that he has to trust that Iran will permit verification, and they have already said they will not allow any inspection of military facilities, no examination of Parchin, and no cameras in any facilities. Furthermore, no facilities will be destroyed and they will keep thousands of centrifuges.

Netanyahu continues to rail against the agreement and to repeat the mantra that Iran poses an existential threat to Israel. If true, he should have no choice but to neutralize the danger.

The pro-Israel community must also face up to its 1930s moment and prove “never again” is not just a slogan. If the community shares the belief that Iran is an existential threat, it also has an obligation to take action.

Some may argue that supporting congressional legislation is the best way to fight the existential threat. In truth, it’s not. Congress does not have the power to stop Iran from getting a nuclear weapon and, even if a veto-proof majority is rallied (and it’s doubtful enough Democrats will defy their president), the proposed legislation will only create the possibility of killing a bad deal and, maybe, sustaining sanctions for an extended period. This assumes the president doesn’t assert executive authority and ignore it altogether, which he says he intends to do.

Meanwhile, the P5, now minus 1, will continue to seek an accommodation with Iran and take advantage of all the business opportunities that Americans will be denied. Russia has already agreed to sell a weapons system to Iran and countries like China and several other Asian and Western nations never stopped doing business with Iran.

In 1939, legislation was proposed to save thousands of Jewish children, but it was opposed by President Roosevelt and never came to a vote. Most Jews were afraid to take on the president, especially one whom they lionized. Today, many Jews are still afraid to speak truth to power. They overwhelmingly voted for Obama and don’t want to believe he would let any harm come to Israel. They also don’t want to become persona non grata at White House functions and, more seriously, risk the president blaming Jews for the failure to reach an agreement to avoid war. Obama has painted opponents of his deal as warmongers and Jews do not want to be scapegoats if the deal collapses.

The question is critical then: Is the Iranian threat truly existential? If so Israel and its supporters have no choice but to do everything possible to eliminate that threat. American Jews cannot cower in the face of a president’s anger and threats if “never again” is to have any meaning.

If the “existential threat” is not really existential, you can ignore all of the above.

Dr. Mitchell Bard is the author/editor of 24 books including The Arab Lobby and Death to the Infidels: Radical Islam’s War Against the Jews.