(Nov. 10) -- As the House prepares to take up a proposed ban on abusive treatment of terrorism suspects, the Republican-led Congress appears headed toward a collision with President Bush.

It's a fight over treatment of prisoners by U.S. interrogators that pits Bush against usual allies, such as Senate Majority Leader Bill Frist, and prominent veterans, such as Sen. John McCain, R-Ariz.

Bush is threatening to veto two major defense bills because they include an amendment to ban abusive treatment of detainees that the Senate has attached to both measures. Bush has never vetoed a bill, but it's unclear if that prospect will be enough to persuade the House of Representatives to excise the ban. The Senate plans to send one of the defense bills to the House today. The other is pending before congressional negotiators.

Acting House Majority Leader Roy Blunt, R-Mo., says Bush and Vice President Cheney have lobbied House Republicans to oppose the amendment, but Blunt stopped short of saying he would urge members to vote no. "It's hard to imagine it wouldn't get a lot of votes," he said. In the Senate, the torture ban was approved 90-9.

The amendment would ban "cruel, inhuman, or degrading treatment or punishment" of any person in U.S. custody, regardless of location or nationality. It was authored by McCain, who was a prisoner of war in Vietnam.

In the House, the ban is backed by another Vietnam combat veteran, Rep. John Murtha. The conservative Pennsylvania Democrat wrote in a letter to House colleagues that revelations about abuses of prisoners in U.S. custody are "degrading our society and its political and legal systems." He says he has the votes - including some Republicans - to win House approval of McCain's amendment.

Bush and Cheney oppose the measure because they say it would limit interrogators' ability to get information from terrorism suspects. Congress shouldn't interfere with "what we are trying to do to detain and interrogate the worst of the worst," says Senate Intelligence Committee Chairman Pat Roberts, R-Kan., a supporter of the administration's position.

Bush insists the U.S. government does not engage in torture. But the McCain amendment is coming before Congress as questions about U.S. policy toward prisoners are growing. Reports by the group Human Rights Watch and The Washington Post that the CIA is holding detainees at secret detention centers have heightened concerns. The CIA has refused to comment on whether the sites exist.

"They lost my trust when they did that," says Murtha, who sits on the panel that determines funding for the Pentagon and CIA. "By not telling us, they lied."

Murtha says that to win over public opinion in Iraq, the United States must dispel any notion it is engaging in torture. In his letter to House colleagues, he says the absence of a clear policy against torture "endangers U.S. servicemembers who might be captured."

McCain, who was tortured by his North Vietnamese captors, argues that abuse does not elicit useful information because "under torture, a detainee will tell his interrogator anything to make the pain stop."

He rejects a compromise proposed by Cheney to excuse the CIA from his proposed ban. "There can be no exemptions," he said.

McCain's strategy is to attach the amendment to bills that will be hard for his colleagues or Bush to reject. He tacked it onto a Pentagon spending bill that contains all military funding, including for the war in Iraq. He also attached it to a bill that authorizes Pentagon programs for next year. "We will win sooner or later," he said. "I will not quit."