WASHINGTON (AP) — Five months after the CIA sought out and killed an American-born cleric and al-Qaida operative in Yemen, Attorney General Eric Holder is expected to explain how the U.S. can legally kill U.S. citizens on foreign soil.

According to the official, Holder plans to say in a major speech on Monday at Northwestern University law school in Chicago that lethal force is legal under a Sept. 18, 2001, joint congressional resolution.