“In our view, if individual Americans choose to take up arms against the United States as part of an opposing fighting force, there will clearly be circumstances in which the president has the authority to use lethal force against those Americans,” the letter stated. “It is vitally important, however, for Congress and the American public to have a full understanding of how the executive branch interprets the limits and boundaries of this authority, so that Congress and the public can decide whether this authority has been properly defined, and whether the president’s power to deliberately kill American citizens is subject to appropriate limitations and safeguards.”

The Senators said the administration’s response to their request might affect their consideration of John Brennan’s nomination to be the next Director of the Central Intelligence Agency. Brennan will testify before the Senate Intelligence Committee on Thursday.

“The executive branch’s cooperation on this matter will help avoid an unnecessary confrontation that could affect the Senate’s consideration of nominees for national security positions,” the lawmakers wrote.

Wyden has requested the secret legal opinions several times without success, including once from Brennan, the White House counterterrorism adviser.