A bipartisan chorus of political and legal voices is calling on the Obama administration to release a declassified version of the Justice Department memo that provided the legal analysis sanctioning the killing in Yemen last week of Anwar al-Awlaki, a U.S. citizen.

They said that the reasoning behind the extraordinary step of killing an American cannot be kept secret from scrutiny if the public is to continue to support counterterrorism operations. Awlaki was killed in a CIA drone strike.

“While U.S. counterterrorism operations are, by necessity, classified, I do believe the administration should make public its legal analysis on its counterterrorism authorities, whether in the form of a legal opinion or a white paper,” said Sen. Dianne Feinstein (D-Calif.), chairman of the Senate Select Committee on Intelligence. “For both transparency and to maintain public support of secret operations, it is important to explain the general framework for counterterrorism actions.”

Sen. Carl Levin (D-Mich.), chairman of the Senate Armed Services Committee, also said this week, “I would urge them to release the memo. I don’t see any reason why they shouldn’t.”

The White House did not respond to a request for comment. A Justice Department spokeswoman declined to comment.