American militants like Anwar al-Awlaki are placed on a kill or capture list by a secretive panel of senior government officials, which then informs the president of its decisions, according to officials.

There is no public record of the operations or decisions of the panel, which is a subset of the White House’s National Security Council, several current and former officials said. Neither is there any law establishing its existence or setting out the rules by which it is supposed to operate…

Two principal legal theories were advanced, an official said: first, that the actions were permitted by Congress when it authorized the use of military forces against militants in the wake of the attacks of September 11, 2001; and they are permitted under international law if a country is defending itself.

Several officials said that when Awlaki became the first American put on the target list, Obama was not required personally to approve the targeting of a person. But one official said Obama would be notified of the principals’ decision. If he objected, the decision would be nullified, the official said.