Former White House strategist Steve Bannon frustrated lawmakers this week when he declined to answer many of their questions about his time in the Trump administration.

To hear members of the House Intelligence Committee tell it, Bannon was using the concept of executive privilege to evade legitimate oversight from Congress.

At the podium Wednesday, White House press secretary Sarah Huckabee Sanders disagreed.

"This White House is following the same practice that many before us have, that have gone back decades," Sanders said. "We encourage the committees to work with us to find the appropriate accommodation in order to ensure Congress obtains all the information that they're looking for."

Lawyers from both political parties who have worked in the White House said the Trump administration's approach to the privilege is not so out of line with previous presidencies.

Executive privilege is not enshrined in the Constitution, but the idea that it's important to protect internal deliberations so a president can receive candid advice is very old. Dwight Eisenhower coined the term, and since then, lots of White Houses have used it to try to shield documents and conversations on sensitive subjects.

Bannon's use of the privilege to avoid answering questions about the transition period is unusual, the lawyers said. That's because there is very little law to support keeping secrets in that period, and because there's one president at a time. From November 2016 until January 2017, that president was Barack Obama.

But, the lawyers said, when it comes to Bannon's time in the White House, his refusal to provide information to Congress is in line with prior administrations. Attorney General Jeff Sessions adopted a similar approach in congressional testimony last year, when he declined to talk about his conversations with President Trump about Russia or his conversations with the president about special counsel Robert Mueller.

Back then, the attorney general indicated the White House might formally assert privilege to block his testimony. But the White House didn't go so far as to send a letter to Capitol Hill to trigger that process.

Former Obama administration lawyers said asserting the privilege often happens late in the process, after negotiations with Congress have broken down. In those cases, the privilege can help serve as a defense or a "get out of jail free card" for an official held in contempt of Congress. That happened to Obama's attorney general, Eric Holder, over documents related to the Fast and Furious scandal, and to George W. Bush aides Joshua Bolten and Harriet Miers, in the scandal after the firing of U.S. attorneys.

Asserting the privilege typically prompts court fights that can drag on for years, into a new administration. For example, the Obama lawyers defended the Bush officials, on the grounds that the principle was more important than the politics.

But the shield of executive privilege does have its limits. In court precedent that goes all the way back to U.S. v Nixon, judges have balanced the president's need for candid, confidential advice against a need for evidence in grand jury proceedings or criminal trials. That's where the special counsel probe is now.

So, Bannon and some of the other people who have been asked to sit for interviews with Mueller's team have to answer prosecutors' questions, unless they invoke their right to remain silent under the Fifth Amendment.

Even Trump's White House counsel, Don McGahn, has to answer. The top appeals court in D.C. doesn't recognize attorney-client privilege when it comes to federal crimes. That decision dates to 1998, when Whitewater special counsel Ken Starr was investigating Bill Clinton's relationship with Monica Lewinsky.

On Tuesday, the same day as Bannon's nearly 11-hour session with the House Intelligence Committee, Lewinsky tweeted on the 20th anniversary of her interview with Starr's investigators. That was two decades ago, but it's relevant again now.

Copyright 2023 NPR. To see more, visit https://www.npr.org.