On December 4, 1981, President Reagan signed Executive order 12333, on the powers and responsibilities of intelligence agencies. It reiterated an important provision of previous executive orders: "No person employed by or acting on behalf of the United States Government shall engage in, or conspire to engage in, assassination."
This executive order is still in effect. Did the bin Laden killing violate it?
According to the Congressional Research Service, the original ban and its successors "were responding to concerns raised with respect to killing of foreign officials or heads of state, and may not have been intended to extend to killing of others." Bin Laden was not a government official.
Moreover, Public Law 107-40, which Congress passed a week after the September 11 attacks, authorizes the president to "use all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons, in order to prevent any future acts of international terrorism against the United States by such nations, organizations or persons."
"The operation in which Osama bin Laden was killed was lawful," Attorney General Eric Holder told the Senate Judiciary Committee. "He was the head of al-Qaida, an organization that had conducted the attacks of September 11th. He admitted his involvement and he indicated that he would not be taken alive. The operation against bin Laden was justified as an act of national self defense."