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Eight former U.S. ambassadors to the United Nations (search) sent a letter on Tuesday urging congressional leaders to reject a bill that would link reform of the world body to payment of American dues, warning that the legislation could actually strengthen opponents of reform.

The letter, coordinated by a nonprofit group that promotes United Nations causes, said there is consensus for U.N. reform (search) but argued that holding back dues would plunge the United States back into the type of bitter fight with fellow member states that broke out when dues were withheld through much of the 1990s.

"Withholding our dues to the U.N. is the wrong methodology," the letter said. "When we last built debt with the U.N., the United States isolated ourselves from our allies within the U.N. and made diplomacy a near impossible task."

The letter was signed by eight former ambassadors, from both Republican and Democratic administrations: Madeleine Albright (search), John Danforth, Richard Holbrooke (search), Jeane Kirkpatrick, Donald McHenry, Thomas Pickering, Bill Richardson and Andrew Young.

The Better World Campaign, which organized the appeal, said the only two other living former U.S. ambassadors to the U.N. were not asked to sign — former President George H.W. Bush because of his ties to his son, President Bush, and John Negroponte because he is still in government, as national intelligence director.

Representative Henry Hyde, R-Ill., has proposed legislation before the U.S. House of Representatives that would require the United States to withhold up to 50 percent of U.S. dues if the United Nations doesn't implement a range of reforms. The bill is scheduled to come up for a vote before the House on Thursday.

Hyde argues that reform will be impossible without the threat of withholding dues. The bill's chances of becoming law in its current form are not clear because President Bush has said he opposes the tactic and there is no identical bill before the U.S. Senate.

The United States is the biggest financial contributor to the United Nations, paying about 22 percent of its annual $2 billion general budget. After the U.S. government fell millions of dollars behind in arrears in the late 1990s, the United States almost lost its voting rights in the General Assembly.

The letter said that withholding money again would "create resentment, build animosity and actually strengthen opponents of reform."

"The fact is reforms cost money and withholding dues impair the U.N.'s ability to make the changes needed," it letter said.