If electoral pressure and persuasion dont work AIPAC has been known to threaten politicians who appear reluctant to follow its lead.

In 2006 Congresswoman Betty McCollum (D-MN) was a liberal with a solid pro-Israel voting record. But she opposed the AIPAC-backed Palestinian Anti-Terrorism Act. The measure sought to impose draconian measures on Palestinian Authority after election of Hamas. It was also opposed by State Department, the Catholic Bishops, and other pro-Israel groups like Americans for Peace Now and Israel Policy Forum.

An AIPAC lobbyist told McCollum chief of staff that her opposition was “support for terrorists” and that this “will not be tolerated.” That was AIPAC’s accusation, not a fact. The threat led McCollum to demand an apology from AIPAC chief Howard Kohr. She also barred AIPAC representatives from her offices.

The basic message is clear: any senator or representative who crosses AIPAC is playing with fire. AIPAC efforts are hardly the only reason some defeated candidates faced electoral challenges and eventually lost. For example Cynthia McKinney prospects were also damaged by a much-publicized confrontation with a Capitol Hill security guard. Lincoln Chafee faced an uphill battle given anti-Republican sentiment in 2006. But AIPAC ability to affect a politician electoral prospects is well known.

As one congressional source put it in 1991 “Voting against Israel has become like voting against lumber in Washington state, except AIPAC does it all over the country.”

Morris Amitay was former AIPAC director who later served as treasurer. He said in 2002 that “everyone seems to be very good nowadays.” Jimmy Carter said in February 2007 that “I dont see any present prospect that any member of the US Congress, the House or Senate, would say, ‘Lets take a balanced position between Israel and the Palestinians and negotiate a peace agreement.’” He added “It’s almost politically suicidal… for a member of the Congress who wants to seek reelection to take any stand that might be interpreted as anti-policy of the conservative Israeli government.”

Source: The Israel Lobby and U.S. Foreign Policy