Senate Intelligence Chair Dianne Feinstein (D-Calif.) accused the CIA of breaking the law by searching her committee's computers. The Post's Karen Tumulty, Scott Wilson, Terence Samuel and Adam Goldman explain the impact in Washington. (Julie Percha and Theresa Poulson/The Washington Post)

To save his run for the Democratic presidential nomination six years ago, then-Sen. Barack Obama turned to author William Faulkner for assistance in explaining how U.S. history has a way of shadowing its present politics.

“The past isn’t dead and buried,” Obama said, slightly embellishing the famous quote in his speech about race. “In fact, it isn’t even past.”

On Tuesday, the past again proved alive for Obama, who now faces a political quandary less personal but still fraught with history.

At the core of the accusations over whether the CIA spied on its Senate overseers is the legacy of Sept. 11, 2001 — and the full public accounting of U.S. actions in its aftermath that has never occurred.

The issues involved span two presidencies from two parties, and have placed a group of powerful Democratic senators against John Brennan, a trusted adviser whom Obama chose to head the CIA.

“It’s important to stand back and look at what we’re talking about here,” White House press secretary Jay Carney told reporters Tuesday. “We are talking about an investigation into activities that occurred under the previous administration, that then-candidate Barack Obama strenuously opposed, that he promised to end, and which he ended very shortly after being sworn into office.”

How Obama manages another political fight between Congress and the intelligence community — as well as a possible Justice Department investigation of the allegations — will have implications for his record as the post-9/11 president.

This one, like the argument over the National Security Agency’s widespread collection of phone and Internet records, is clouded by partisanship and political inheritance, although with an added element of personal loyalty. Carney said Tuesday that “the president has great confidence in John Brennan and confidence in our intelligence community and our professionals at the CIA.”

From ending two wars to prohibiting the interrogation practices at issue in the current debate, Obama has made moving the country beyond what he described as a “season of fear” a central element of his legacy in office. But doing so has been difficult.

The U.S. military prison at Guantanamo Bay, Cuba, that he promised to close remains open. A more coherent and publicly accountable framework for the use of drones is unfinished. The scope and legality of U.S. eavesdropping has been revealed as vast and largely unchecked.

“We have made mistakes — more than a few — and we have tried mightily to learn from them,” Brennan said Tuesday in an appearance at a Council on Foreign Relations event. “Even as we have learned from the past, we must also be able to put the past behind us so we can devote our full attention to the challenges ahead of us.”

Brennan was a senior CIA official under George W. Bush at a time when interrogation methods that the International Committee of the Red Cross characterized as torture were being used. The agency also operated a series of “black sites” overseas where it held and interrogated terrorism suspects.

Obama campaigned against those practices, then named Brennan as his chief counterterrorism adviser after taking office in early 2009.

The new president moved quickly to distinguish himself from his immediate predecessor, arguing that national security policy in the age of international terrorism was not inconsistent with the rule of law.

The left wing of his party, among others, hoped for a public reckoning for Bush administration officials who sanctioned torture, the word Obama used to describe the interrogation methods. He chose not to take that course, urging the country to move on and do better.

“I recognize that many still have a strong desire to focus on the past,” Obama said in May 2009 at the National Archives. “When it comes to actions of the last eight years, passions are high.”

A few weeks earlier, Obama had authorized the release of Bush-era legal opinions that sanctioned the use of harsh interrogation methods, angering conservatives and prompting demands for more accountability from frustrated liberals.

At the National Archives that day, Obama acknowledged that “some Americans are angry” and “others want to re-fight debates that have been settled, in some cases debates that they have lost.”

“The Congress can review abuses of our values, and there are ongoing inquiries by the Congress into matters like enhanced interrogation techniques,” he said.

Later that day, former vice president Richard B. Cheney spoke at the American Enterprise Institute, offering a pointed rebuttal to Obama’s remarks.

“I was and remain a strong proponent of our enhanced interrogation program,” he said. “The interrogations were used on hardened terrorists after other efforts failed. They were legal, essential, justified, successful and the right thing to do.”

Cheney said the techniques Obama denounced hours earlier “prevented the violent death of thousands, if not hundreds of thousands, of innocent people.”

“Our successors in office have their own views on all of these matters,” Cheney said. “For reasons the administration has yet to explain, they believe the public has a right to know the method of the questions, but not the content of the answers.”

In many ways, the virtual debate that took place that day in May has guided the argument in Washington over torture, terrorism and disclosure ever since — leading to the tension between the CIA and the Senate Select Committee on Intelligence that emerged publicly on Tuesday.

The intelligence panel’s 6,500-page report was envisioned, in part, to put the issue to rest. It was adopted 14 months ago and concluded, among other things, that no valuable intelligence was gained through interrogations that involved torture.

The Obama administration has supported declassifying the report’s findings. Chairman Dianne Feinstein (D-Calif.), whose criticism of the CIA officially brought the debate to light, is moving to do that soon.

At the same time, the Justice Department is considering a CIA inspector-general referral that could lead to the prosecution of any agency staff members involved.

“As a country, we should never go down this road again, and part of making sure we don’t is understanding what happened,” said Christopher E. Anders, senior legislative counsel at the American Civil Liberties Union. “It’s not just some historic interest. We must understand how we got there and we must make sure that if there is formal accountability that should happen, then it can happen.”