The rift is most notable between top attorneys at the departments of State and Defense, although a review of legal briefs and interviews indicate the conflict about the powers left by the George W. Bush administration also includes career Justice Department officials and political appointees in national security posts, the Times said.
Discussions center on how broadly defined are the types of terrorism suspects who may be detained without trials as wartime prisoners, the Times said.
The fissure is apparent when examining secret memos produced by Harold Koh, a former human-rights official and a leading critic of the Bush administration's detainee policies who became the State Department's top lawyer in late June, and the Pentagon's top lawyer Jeh C. Johnson, an adviser to Barack Obama during his presidential campaign, the Times said.
Johnson argued in his secret memo for a more fluid interpretation of who could be detained under the laws of war and Koh did not.
"Beyond the technical legal issues, this debate is about the fundamental question of whom we are at war with," said Noah Feldman, a Harvard University law professor specializing in war power issues. "The two problems most plaguing Obama in the war on terrorism are trials for terrorists and taking the fight beyond Afghanistan to places like Pakistan and Yemen. This issue of whom we are at war with defines both of them."