Republicans and Democrats took to the Senate floor on Wednesday in a passionate debate over the measure, which supporters said would clarify a jumble of conflicting standards and cast a new spotlight on the treatment of detainees at American prisons in Afghanistan, Iraq and Cuba. "Confusion about the rules results in abuses in the field," said Senator John McCain, an Arizona Republican and the measure's main sponsor. "We need a clear, consistent standard."

Mr. McCain, who was a prisoner of war in the Vietnam War, added in closing Wednesday night: "Many of my comrades were subjected to very cruel, very inhumane and degrading treatment, a few of them even unto death. But every one of us -- every single one of us -- knew and took great strength from the belief that we were different from our enemies."

Senator Lamar Alexander, a Tennessee Republican, questioned why the White House would oppose a measure that codifies military procedures and policies, and reaffirms a ban against torturing detainees. "It is time for Congress, which represents the people, to clarify and set the rules for detention and interrogation of our enemies," he said.

Opposing the effort, Senator Ted Stevens, Republican of Alaska, said that requiring American troops to follow procedures in the Army manual was not practical in the current war environment. "The techniques vary upon the circumstances and the physical location of people involved," Mr. Stevens said

The measure faces stiff opposition in the House. And the White House spokesman, Scott McClellan, said, "If it's presented, then there would be a recommendation of a veto." Armed with the strong Senate vote, however, Mr. McCain is expected to keep the pressure on in the public arena and when the spending bill goes to a House-Senate conference committee.