WASHINGTON – It will be the DC equivalent of the showdown at the OK Corral. Stepping into the summer haze on Capitol Hill, the American Israeli Public Affairs Committee and its allies are set to face off against the ultimate power broker – 1600 Pennsylvania Avenue – backed up by a cadre of its allied groups.

The lobbying showdown, over a Congressional vote on the nuclear deal with Iran, represents a rare moment for AIPAC, with the avowedly bipartisan organization publicly splitting with the sitting administration over a major foreign policy initiative.

Even at the peak of tensions between the Obama administration and the Israeli government earlier this year, when Prime Minister Benjamin Netanyahu’s speech before Congress coincided with the AIPAC policy conference’s lobbying day, the pro-Israel organization worked hard to keep its head above an ugly fray.

AIPAC’s efforts at bipartisanship, and specifically at avoiding picking a fight with the president, extend back decades. For years, the organization has maintained a policy of remaining tight-lipped on budgetary face-offs, preferring instead to focus on completed deals and lobbying successes.

Guests photograph US President Barack Obama as he speaks during a reception for the 25th anniversary of the Americans with Disabilities Act (ADA) in the East Room of the White House in Washington, DC, July 20, 2015 (AFP PHOTO / SAUL LOEB)

Guests photograph US President Barack Obama as he speaks during a reception for the 25th anniversary of the Americans with Disabilities Act (ADA) in the East Room of the White House in Washington, DC, July 20, 2015 (AFP PHOTO / SAUL LOEB)

On Iran, the fight has been growing increasingly rancorous. AIPAC publicly backed legislation sponsored by senators Mark Kirk and Bob Menendez that would have threatened Iran with additional sanctions if talks had failed – a bill that the administration fervently opposed.

The administration has accused skeptics of the Iran deal of suggesting no alternative short of war, and in a lengthy press conference Wednesday, President Barack Obama warned Congress against being swayed by “lobbyists” – suggesting that deal opponents were not concentrating solely on the US interest.

Benjamin Netanyahu finishes his address to the American Israel Public Affairs Committee (AIPAC) policy conference in Washington on March 4, 2014.  (photo credit: AFP/Nicholas Kamm)

Benjamin Netanyahu finishes his address to the American Israel Public Affairs Committee (AIPAC) policy conference in Washington on March 4, 2014. (photo credit: AFP/Nicholas Kamm)

While such a scrap between AIPAC and the administration is not without precedent, it has been over two decades since the last bare-knuckles fight.

In fact, longtime Washington insiders can only recall two other cases in the past 40 years in which the organization took on the president. Significantly to this battle, neither instance ended with a clear win for the pro-Israel lobby. Such standoffs remain so sensitive that few involved are willing to discuss publicly the dramas of past decades.

No guarantees with George H.W. Bush

Throughout recent months, pundits have compared the current bad blood between Netanyahu and Obama to the relationship between president George H.W. Bush and prime minister Yitzhak Shamir – a notoriously rocky one that led to the last public clash between AIPAC and the president.

US president George H. Bush meets with prime minister Yitzhak Shamir in the Oval Office of the White House in Washington on Tuesday, December 11, 1990 (AP Photo/Barry Thumma, File)

US president George H. Bush meets with prime minister Yitzhak Shamir in the Oval Office of the White House in Washington on Tuesday, December 11, 1990 (AP Photo/Barry Thumma, File)

In 1991, the Israeli government ran aground in its efforts to secure some $10 billion in loan guarantees from the US government to help settle the massive wave of immigration from the Soviet Union. Bush dug in his heels, even fighting with Congress, in order to withhold the loan guarantees unless all construction in the West Bank and Gaza Strip was halted.

Shamir campaigned directly against Bush, saying that linking loan guarantees and settlement construction was “dangerous” and that he “hope[d] the American people won’t accept the linkage that the administration is trying to create between the two.”

Bush, meanwhile, vowed, “We’re not giving one inch on the settlements question.”

AIPAC and a number of other Jewish organizations rallied their supporters to push Congress to buck Bush’s policy. One thousand Jewish activists from across the United States arrived on Capitol Hill immediately after Rosh Hashanah, the Jewish new year, to lobby their representatives to approve the loan guarantees.

In a news conference that same day, Bush lambasted AIPAC and the pro-Israel mobilization, saying that his administration was “up against very strong and effective, sometimes, groups that go up to the Hill. I heard today there were something like a thousand lobbyists on the Hill working the other side of the question. We’ve got one little guy down here doing it.”

Bush’s remarks earned him the animosity of some American Jews who saw his comments as inappropriate. But the president, entering an election year, refused to budge on the issue, and AIPAC’s might failed to dislodge him.

Only events in Israel brought a resolution to the crisis. Bush was seen to favor the Likud prime minister’s challenger, Yitzhak Rabin, in the upcoming Israeli elections. Less than two months after Rabin defeated Shamir, he and Bush reached an agreement on loan guarantees.

AIPAC vs. AWACS

As Ronald Reagan’s vice president, Bush had already been given a bird’s-eye view of an AIPAC-White House fight.

In 1981, AIPAC and the Reagan administration engaged in a bitter face-off over the proposed sale of E-3 Airborne Warning and Control System (AWACS) aircraft to Saudi Arabia. When the administration announced plans to sell five of the aircraft to the Saudis, Israel fiercely opposed the transfer as limiting Israel’s ability to apply its surprise first-strike strategy, a linchpin of the Israeli military doctrine of taking the fight to the enemy as quickly as possible.

In a striking prefiguration of claims by opponents of the nuclear deal with Iran, challengers of the sale warned that it would both endanger Israel’s security and, according to an editorial in the Boston Globe, “further destabilize the Mideast, a region whose stability was supposed to be a strategic priority of the Reagan foreign policy.”

The administration took on AIPAC and Israel’s opposition head first. Secretary of State Alexander Haig complained about “the restraints of overriding external vetoes” and threatened “serious implications on all American policies in the Middle East” if Israeli influence blocked the deal.

Prime minister Menachem Begin, left, is escorted by secretary of state Alexander Haig on Begin's arrival in Washington, Tuesday, September 9, 1981(AP Photo, File)

Prime minister Menachem Begin, left, is escorted by secretary of state Alexander Haig on Begin’s arrival in Washington, Tuesday, September 9, 1981(AP Photo, File)

AIPAC officials described the fight against the sale as the organization’s “top priority.” The group’s executive director at the time, Tom Dine, said that he knew “the administration will be hitting hard at some of our supporters trying to get them to change” but vowed to “keep the pressure on.”

Although Dine said that he believed he had the votes to block the sale, AIPAC ended up losing the battle — Congress voted with the administration to approve the sale.

But despite the vitriol of that fight, it still falls short of the battle shaping up in Washington today. The AWACS sale was, when push came to shove, a weapons transfer meant to solidify the US-Saudi alliance; it did not hold the same status for the Reagan administration as the landmark Iran deal, which many see as a legacy project of the Obama administration.

President Barack Obama and AIPAC President Lee Rosenberg wave to the crowd gathered at the AIPAC convention in Washington in May 2011. (photo credit: AP/Jose Luis Magana)

President Barack Obama and AIPAC President Lee Rosenberg wave to the crowd gathered at the AIPAC convention in Washington in May 2011. (photo credit: AP/Jose Luis Magana)

This is the first time, Washington old-timers agree, that the self-imposed stakes have been quite so high for the administration. Neither side is likely to retreat, setting the stage for the history-making clash. Only the coming two months will tell whether this showdown will end any differently than the previous ones – or how deep the bad blood will run before it’s done.