Mr. Cheney and some of his aides have spearheaded the administration's opposition to Senator McCain's amendment; they were also quick to oppose a draft of the detention directive, which began to circulate in the Pentagon in mid-September, officials said.

A central player in the fight over the directive is David S. Addington, who was the vice president's counsel until he was named on Monday to succeed I. Lewis Libby Jr. as Mr. Cheney's chief of staff. According to several officials, Mr. Addington verbally assailed a Pentagon aide who was called to brief him and Mr. Libby on the draft, objecting to its use of language drawn from Article 3 of the Geneva Conventions.

"He left bruised and bloody," one Defense Department official said of the Pentagon aide, Matthew C. Waxman, Mr. Rumsfeld's chief adviser on detainee issues. "He tried to champion Article 3, and Addington just ate him for lunch."

Despite his vehemence, Mr. Addington did not necessarily win the argument, officials said. They predicted that it would be settled by Mr. Rumsfeld after consultation with other agencies.

But while advocates of change within the administration have prevailed in a few skirmishes, some of those officials acknowledged privately that proponents of the status quo still dominate the issue -- partly because of the bureaucratic difficulty of overturning policies that have been in place for several years and, in some cases, were either approved by Justice Department lawyers or upheld by the federal courts.

"A lot of the decisions that have been made are now difficult to get out of," one senior administration official said.

A spokesman for the vice president, Stephen E. Schmidt, said Mr. Addington would have no comment on his reported role in the policy debates. A Defense Department spokesman, Bryan Whitman, also would not discuss Mr. Waxman's role except to say it was "certainly an exaggeration" to characterize him as having been bloodied by Mr. Addington.