The agency missed a Feb. 15 deadline to complete a review of the report, which has 35,000 footnotes referring to 6 million documents from C.I.A. files. It now appears likely that the response, offering the committee any factual corrections or broader judgments, will be delayed until Mr. Brennan’s arrival.

Because Mr. Obama famously said he preferred to look forward, not back at his predecessor’s counterterrorism programs, the Senate report is by far the most thorough examination of how the United States came to use nudity, cold, sleep deprivation, stress positions, wall-slamming and waterboarding, methods it had long condemned as abuse or torture.

Mr. Brennan will have to decide whether to support making a redacted version of the interrogation report public, as the committee is likely to support after the C.I.A. completes its review and as a United Nations human rights adviser urged this week. Several Democratic senators and at least one Republican, Senator John McCain of Arizona, who was tortured as a prisoner in North Vietnam, have said that a declassified version must be released, and Mr. Brennan said he would give the request “serious consideration.”

He will have to decide whether to convene what the agency calls an accountability board to recommend punishment for current or former officials accused of mismanaging or misrepresenting the interrogation program. If he tries to keep the peace by dismissing the dispute as history and a distraction from the agency’s current challenges, he will face strong resistance from the Senate committee’s Democratic majority and Mr. McCain.

But Emile A. Nakhleh, a former top C.I.A. analyst on political Islam who once worked for him, said Mr. Brennan’s work as Mr. Obama’s top counterterrorism adviser, intimate knowledge of the agency and blunt style equip him well to handle the task.

“It will be challenging, but if there’s any person who can take this on, it’s Brennan,” Mr. Nakhleh said. “He may say some harsh things about the program, and some people won’t like it. But the institution will benefit.”