WASHINGTON â€” The last time the nationâ€™s most potent pro-Israel lobbying group lost a major showdown with the White House was when President Ronald Reagan agreed to sell Awacs surveillance planes to Saudi Arabia over the groupâ€™s bitter objections.
Since then, the group, the American Israel Public Affairs Committee, has run up an impressive record of legislative victories in its quest to rally American support for Israel, using a robust network of grass-roots supporters and a rich donor base to push a raft of bills through Congress. Typically, they pass by unanimous votes.
But now Aipac, as the group is known, once again finds itself in a very public standoff with the White House. Its top priority, a Senate bill to impose new sanctions on Iran, has stalled after stiff resistance from President Obama, and in what amounts to a tacit retreat, Aipac has stopped pressuring Senate Democrats to vote for the bill.
Officials at the group insist it never called for an immediate vote and say the legislation may yet pass if Mr. Obamaâ€™s effort to negotiate a nuclear agreement with Iran fails or if Iran reneges on its interim deal with the West. But for the moment, Mr. Obama has successfully made the case that passing new sanctions against Tehran now could scuttle the nuclear talks and put America on the road to another war.
In doing so, the president has raised questions about the effectiveness of Aipacâ€™s tactics and even its role as the unchallenged voice of the pro-Israel lobby in Washington. Jewish leaders say that pro-Israel groups disagreed on how aggressively to push the legislation, even if all the groups favor additional sanctions.
â€œSome of us see the object as being to target Iran,â€ said Abraham H. Foxman, the national director of the Anti-Defamation League. â€œWeâ€™re not out there to target the president; weâ€™re out there to target Iran.â€
With neither side spoiling for a fight or ready to back down, Mr. Foxman said, the sanctions campaign is stalled. Lawmakers confirm that the political climate on Capitol Hill has changed since the billâ€™s sponsors and Aipac made their push in December.
Senator Richard Blumenthal of Connecticut, a staunch supporter of Israel, is one of 16 Democrats who signed on to the bill, along with 43 of the Senateâ€™s 45 Republicans, bringing it to within a few votes of a veto-proof majority. Now Mr. Blumenthal says the Senate should hold off on a vote to give Mr. Obama breathing room for diplomacy.
â€œThereâ€™s been an unquestionable, undeniable shift in the perception of national security,â€ Mr. Blumenthal said. â€œIâ€™m sensitive to the feelings, the resistance, the aversion of the general public to any kind of American military engagement.â€
On Monday, 70 House Democrats sent Mr. Obama a letter backing his diplomatic efforts and opposing new sanctions. Former Secretary of State Hillary Rodham Clinton added her voice to those urging no legislation.
The billâ€™s chief sponsors insist they are not retreating, with some congressional aides predicting that the White Houseâ€™s tough tactics could backfire down the road.
â€œThe American people â€” Democrats and Republicans alike â€” overwhelmingly want Iran held accountable during any negotiations,â€ said Senator Mark S. Kirk, Republican of Illinois, who is a lead co-sponsor, along with Senator Robert Menendez, Democrat of New Jersey.
But Aipacâ€™s headaches go beyond Iran. In September, it threw an army of lobbyists behind an effort to win a congressional mandate for Mr. Obamaâ€™s threatened military strike on Syria. Facing certain failure in Congress, the president pulled the plug on the effort.
Earlier last year, it came under fire from the right for not publicly opposing Mr. Obamaâ€™s nomination of Chuck Hagel as secretary of defense, because of what critics said was his anti-Israel record.
None of this will prevent Aipac from drawing 14,000 supporters and a whoâ€™s who of speakers from the White House and Congress when it holds its annual meeting here next month. But this yearâ€™s meeting could be more complicated than the one in 2012, when Prime Minister Benjamin Netanyahu of Israel turned out to demand that Mr. Obama threaten Iran with a military strike if it produced a nuclear weapon. The president, who also spoke, promised to keep all options on the table, including military action.
Aipac officials said that their fund-raising is at record levels and that the March meeting will be the largest in its history. The group has helped secure $3.1 billion in American aid for Israel for the fiscal year and largely framed the public debate over Iranâ€™s nuclear program.
â€œUnder any other circumstances, having 59 senators from both parties supporting a bill that has this type of opposition is extraordinary,â€ said a spokesman for Aipac, Marshall Wittmann. â€œFor someone to describe this as a setback is completely preposterous.â€
Mr. Wittmann disputed suggestions that the group had been weakened by its support for the abortive military action against Syria or its decision not to lobby against Mr. Hagel. Mr. Obamaâ€™s threat of force, he said, helped get chemical weapons out of Syria. As for Mr. Hagel, Mr. Wittmann said, â€œour focus is on the policy.â€
Still, in its zeal to pass the bill, Aipac may have overreached. Last month, a regional director for the group came to the defense of Representative Debbie Wasserman Schultz of Florida, the chairwoman of the Democratic National Committee, after Aipac sent a letter urging its members to demand that she clarify her support for sanctions.
In the follow-up letter, emailed to Aipac members in Florida, a national board member, Ike Fisher, declared, â€œCongresswoman Wasserman Schultz has a strong record of support for the U.S.-Israel relationship.â€ Ms. Wasserman Schultz declined to comment.
In another small but telling contretemps, a group of prominent liberal Jews sent a letter last week to Mayor Bill de Blasio of New York, rebuking him for speaking last month at a closed-door gathering of Aipac, which they said â€œspeaks for Israelâ€™s hard-line government and its right-wing supporters.â€
Founded in 1951, a few years after the state of Israel was established, Aipac says its mission is to â€œstrengthen, protect and promote the U.S.-Israel relationship,â€ regardless of the governments in either country.
â€œThe source of Aipacâ€™s power is its ability to generate bipartisan votes,â€ said Steven J. Rosen, a former senior official at the group, who was forced out in 2005 after being caught up in an espionage case.
The trouble is, Aipacâ€™s fervent push on Iran sanctions has increasingly allied it with Mr. Netanyahu and against Mr. Obama. J Street, a more dovish pro-Israel group, has lobbied vigorously against the bill, underscoring divergent views within the pro-Israel lobby.
â€œYouâ€™re seeing, in the American Jewish community, an engagement in the debate in a more complex way,â€ said Representative Peter Welch, a Vermont Democrat. â€œSome say they want sanctions, but some say they support the White House.â€
Even Aipacâ€™s efforts to support the president have been troubled. It had deep reservations about Mr. Hagel, which officials shared privately with lawmakers. But it did not publicly oppose his nomination, in part because White House officials said the president would not forgive it.
â€œA lot of this has been about Obama,â€ said Steve Rabinowitz, who worked in the Clinton administration and advises Jewish groups. â€œThe good news is that his foreign-policy cred has strengthened, and there is increasing deference to the president on foreign policy.â€
Senator Christopher S. Murphy, a freshman Democrat from Connecticut, embodies this trend. After voting for sanctions in the House, he opposed the Senate bill because, he said in an interview, the point of sanctions was to force Iran to the bargaining table.
Mr. Murphy said he was not worried about bucking Aipac. â€œThe pro-Israel community in Connecticut knows Iâ€™m a strong supporter of the U.S.-Israel relationship,â€ he said, â€œand I always will be.â€