WASHINGTON — A bill aimed at isolating the Hamas-led Palestinian government has triggered a major fight between the Jewish community’s main pro-Israel lobby and a member of the House Committee on International Relations.

Rep. Betty McCollum, a Minnesota Democrat, is refusing to meet with representatives of the American Israel Public Affairs Committee until she receives an apology from the lobbying powerhouse.

McCollum says that, in a recent phone conversation with her chief of staff, an Aipac representative accused the congresswoman of supporting terrorists because she voted against the Palestinian Anti-Terrorism Act of 2006 in committee. Aipac — a leading backer of the bill, which was overwhelmingly passed Tuesday by the full House of Representatives — denies McCollum’s accusation and has not issued an apology to the congresswoman.

The feud comes as debate intensifies over the question of how to deal with Hamas, which refuses to recognize Israel or disavow terrorism. On Tuesday, the chief of staff of the Israeli military, Dan Halutz, predicted that economic pressure on the Hamas-led Palestinian government would fail to bring about its downfall. He warned that external pressure could end up boosting popular support for the Islamic fundamentalist organization.

At the same time, Jewish organizations in America were divided over the Aipac-backed bill, which imposes severe limitations on the American government’s ability to maintain relations with or send aid to the Palestinian Authority as long as it is run by Hamas. The House vote was hailed by several influential Jewish organizations, including Aipac. But liberal groups, including Americans for Peace Now and the Israel Policy Forum, have come out against the measure, saying it could undercut America’s and Israel’s national security needs by denying the Bush administration flexibility in dealing with the Palestinian Authority and by deepening poverty and chaos in the territories.

While Aipac’s side carried the day in the House, the organization was still mired in its fight with McCollum, whose district is in St. Paul.

“Until I receive a formal, written apology from your organization, I must inform you that Aipac representatives are not welcome in my offices for meetings with my staff,” McCollum wrote in a recent letter to the organization’s executive director, Howard Kohr.

McCollum’s letter is causing a stir on Capitol Hill, where legislators typically avoid public clashes with the powerful pro-Israel lobby. One Jewish congressman who is known as a leading supporter of Israel and Aipac, Democrat Gary Ackerman of New York, has issued a statement backing McCollum, in which he described the alleged attempt to accuse her of supporting terrorists as “an approach reminiscent of the Taliban.”

Ackerman is said to be trying to broker a meeting between McCollum and Aipac officials.

Congressional staffers said that the controversy is reverberating on the Hill because Aipac officials have a reputation of being overly aggressive in their lobbying style. “Many members of Congress are sick and tired of Aipac’s bullying and heavy-handed tactics,” said a senior congressional staffer, speaking on condition of anonymity.

McCollum is one of two members of the House International Relations Committee who voted against the Palestinian Anti-Terrorism Act of 2006, an Aipac-backed bill that imposes strong limitations on the American government’s ability to maintain relations with or send aid to the P.A. as long as it is run by a Hamas-led government.

In an April 27 statement on the House floor, McCollum highlighted sections in the bill that would make it difficult for the administration and for nongovernmental organizations to provide humanitarian aid to the Palestinians. As a result, she said, the bill would further destabilize the situation on the ground between Israelis and Palestinians “while fueling a humanitarian crisis.”

McCollum, a Catholic who represents a heavily Catholic, liberal district, referred in her statement to a letter sent to her committee’s chairman, Illinois Republican Henry Hyde, by the United States Conference of Catholic Bishops. The letter strongly opposed the bill. The letter, sent one day before the committee voted on the measure, pointed out that assistance programs delivered by Catholic Relief Services in the West Bank and Gaza — as well as other NGO-run programs — could be “severely curtailed” by the bill.

Aipac sources, senior activists in Minnesota’s Jewish community and congressional staffers who know her well, described McCollum as a strong supporter of Israel who has excellent relations with the local Jewish community. McCollum recently invited a prominent Minnesota pulpit rabbi, Morris Allen of Mendota Heights, to be her personal guest for Israeli Prime Minister Ehud Olmert’s address this week to a joint session of Congress.

Stephen Silberfarb, executive director of the Jewish Community Relations Council of Minnesota and the Dakotas, said that although the local Jewish community is disappointed with her vote on the bill, the incident is “isolated” and “it’s not going to be determinative of the entirety of the relationship with her.”

The bill has strong backing from Aipac, which invested a great deal of effort to line up co-sponsors for the measure and to fend off counter-lobbying by dovish Jewish organizations and by several Christian groups.

A senior Senate staffer told the Forward last week that once the bill passes the House, Senate leaders will work hard to soften the version that will end up in the bicameral conference committee. The staffer said that Senate leaders view the House bill as “insanely irresponsible.” Aipac sources, as well as other Jewish groups lobbying for the bill, said that they would vigorously oppose any attempts to water down the measure.

As part of Aipac’s lobbying blitz, right after the International Relations Committee passed the measure in a 36-2 vote, Amy Rotenberg, an active member of the organization from Minneapolis, called McCollum’s chief of staff, Bill Harper. Aipac sources said that the purpose of the April 7 call was to express disappointment over the congresswoman’s vote against the bill. According to Harper, Rotenberg said that “on behalf of herself, the Jewish community, Aipac, and the voters of the Fourth District, Congresswoman McCollum’s support for terrorists will not be tolerated.”

McCollum sent her letter to Aipac following the phone conversation. The letter was first published in the current issue of the New York Review of Books, accompanying a long essay by journalist Michael Massing suggesting that Aipac often uses its considerable weight to intimidate or punish legislators for not supporting its agenda. On Monday, Congressional Quarterly, one of the most influential publications among congressional staffers, mentioned in a front-page story the fight between McCollum and Aipac.

In a letter to McCollum and in a conversation with the Forward last week, Rotenberg, an attorney who specializes in media law and is active in Minnesota Democratic politics, flatly denied Harper’s account, describing it as a “serious distortion of the discussion.” Rotenberg contends that McCollum’s chief of staff asked if the Aipac activist was accusing the congresswoman of supporting terrorists. In response, Rotenberg said, she replied that she was not, adding that the vote would have to speak for itself.

Harper says that he stands by his account of the conversation “one-hundred percent.”

Rotenberg has made several offers in letters and phone calls to the congresswoman’s office to iron things out — but McCollum has rejected all the efforts. The congresswoman is also refusing to meet with Kohr, Aipac’s executive director.

“Our letter is clear. We will not meet with them until there is a formal apology,” Harper said, adding, “This is about respect for the office of the congresswoman and her constituency.”

A spokeswoman for Aipac declined to comment on the affair and said that Rotenberg’s letter speaks for itself.

For an expanded version of this article, visit www.forward.com.