The American Israel Public Affairs Committee is one of the most important and powerful organizations in the Jewish and pro-Israel community.It plays a vital role in preserving and enhancing the US-Israel alliance.However, on the most important issue affecting Israel’s future in a generation – the Iran nuclear deal – AIPAC failed to deliver. Why was AIPAC unable to prevent this catastrophic agreement from leaving Israel facing another genocidal threat? AIPAC has taken fire from multiple directions over its opposition to the nuclear agreement. Anti-Semites who for years have speciously claimed the “Jewish lobby” is omnipotent are, paradoxically, gloating over its defeat. Many AIPAC supporters, especially Democrats, are furious that AIPAC challenged the president on what they believe is his legacy foreign policy achievement.I believe it was impossible for AIPAC to sit on the sidelines when the government and opposition in Israel agreed that Iran’s nuclear ambitions pose an existential threat to the Jewish state. Many supporters of AIPAC, like me, are less angry than disappointed that the lobby was not more effective. We knew that this was an uphill battle; after all, the president is the most powerful lobbyist and, given the tradition that politics stop at the water’s edge, Congress rarely challenges policies relating to national security. Still, I believe AIPAC could have been more effective in defeating this disastrous deal. According to a close friend on AIPAC’s national board, even AIPAC is doing its own soul-searching through an internal review.AIPAC can save a lot of time and money on consultants if its leaders acknowledge they failed to exert enough pressure on members of Congress because of their reluctance to publicly target them. I recognize that AIPAC faces a Catch-22: On one hand, it must have access to decision-makers to influence policy, and to demonstrate to its donors that it has clout; on the other hand, the fear of losing that access sometimes leads AIPAC to hold its fire. The risk of losing access to the White House, for example, is one of the main reasons AIPAC has very rarely publicly opposed the president’s policies. Once AIPAC decided to take on the president, however, it needed to go to the mat to win, but, instead, it pulled its punches.AIPAC supposedly spent $40 million on the campaign to stop the nuclear deal.What did it achieve with all that money? It may have helped win a total of one vote, Sen. Joe Manchin of West Virginia, who courageously defied his party. The other three Democrats were probably unaffected by the campaign. Sen. Robert Menendez of New Jersey, arguably Israel’s greatest friend in the Senate, came out strongly and early against the deal. New York’s Sen.Charles Schumer was under great pressure from his supporters and the White House and, ultimately, angered both by opposing the deal but refusing to lobby his colleagues to join him. Sen. Ben Cardin came out against the agreement late, after it was clear the president had won.The weakness of AIPAC’s campaign was that it focused on the general message that Congress should insist on a better deal with Iran. Ads asked the public to call their lawmakers to oppose the deal.This was the wrong approach. Instead, the ads should have targeted members by name. They should have documented the promises each member made to the community related to Israel’s security and say that the voters who put them in office will hold them accountable for reneging on those commitments.Politicians do listen to reasoned arguments and they of course try to make moral judgments. But they largely make decisions based less on the persuasiveness of lobbyists than on how they will be perceived by their constituents and how much they risk provoking a challenge in the next election. Unlike President Obama, AIPAC failed to put elected leaders on notice by sending an unequivocal message that there would be political and electoral consequences if they did not vote against an agreement that legitimized a genocidal government. Worse, almost immediately after the vote, AIPAC began to have kiss and make up meetings with members to put the nastiness behind them and return to the status quo ante.There is no better way to demonstrate ineffectiveness than to communicate the message that the lobby can be defied with impunity.It is not too late for AIPAC to stand up for American values. Rather than forgive and forget the failure of members of Congress to vote against the catastrophic Iran deal, AIPAC should demand that they atone for their misjudgment. Instead of inviting members to their events or supporting their reelection, they should first insist they vote to strengthen Israel’s qualitative edge, impose sanctions for violations of UN resolutions related to ballistic missiles, and delay the lifting of any sanctions by a minimum of 60 days every time Iran repeats its genocidal threats against Israel.If an elected official does not oppose public calls to genocide, can they be trusted on any other matter? The impact of AIPAC’s defeat is devastating.It created the impression that the pro-Israel community, and the special relationship between the United States and Israel, has been weakened. President Obama accomplished what the Arab lobby could not; namely, driving a wedge between the United States and Israel.The long-run damage from AIPAC’s failure to defeat the Iran deal is more ominous.Iran has now been recognized as a threshold nuclear state. Even under the rosiest scenario, in which Iran is constrained from building nuclear weapons during the life of the agreement, there is no assurance that Iran will not develop a nuclear weapon after restraints are lifted in 15 years, a blink of an eye in the timeline of Middle East history.This may be AIPAC’s most consequential defeat, but it is not the first time it has lost and probably will not be the last. AIPAC remains a bulwark against the efforts of J Street and others who wish to paternalistically substitute their judgment for that of the people of Israel, and lobby the government to pressure Israel to give in to the demands of J Street’s members sitting comfortably 6,000 miles away, where they do not have to live with the consequences of their dangerous and ill-informed policy prescriptions.AIPAC must regain its stature as the most powerful foreign policy lobby. It cannot do so, however, by shying away from fights that may buck the odds and the political winds, but still need to be fought on principle.AIPAC also must prove that it is too influential to ignore and that officials who put political considerations before preventing genocide – and electoral consideration before morality – will rue the day.The future of Israel and the US-Israel relationship, and the preservation of American and democratic values in the Middle East is too important to play political softball.The writer is the founder of The World Values Network and author of 30 books, including his most recent, The Israel Warriors Handbook. Follow him on Twitter @ RabbiShmuley.