LEAK A KEY FACTOR-HOLDER
Separately, a Justice Department document on circumstances in which Americans could be killed if they were involved in militant activities overseas was leaked to NBC News last month.
Holder said on Wednesday that the debate started by the leaking of that document was "one of the strongest reasons" why it made sense to share the Office of Legal Counsel memos with Congress.
Senators on Wednesday also questioned Holder over whether the Obama administration would ever countenance using drone strikes to target citizens on American soil.
In a letter to Kentucky Republican Senator Rand Paul, which was made public on Tuesday, Holder said drone strikes against Americans on U.S. soil were not anticipated, but he did not rule them out in circumstances akin to the September 11, 2001, attacks.
Texas Republican Senator Ted Cruz questioned Holder about whether it could ever be legal to launch strikes against U.S. citizens on U.S. soil unless that individual was an imminent threat.
"I would not think that would be an appropriate use of any lethal force," Holder said.
Cruz said he intends to introduce legislation that would clarify when deadly force against U.S. citizens on American soil could be used.
Obama to reveal more on drone strike policy: attorney general