The September 2011 drone strike that killed American citizens Anwar al-Awlaki and Samir Kahn has been the focus of intense debate for the last three years. Now, thanks to a new report from The New York Times, we know how the U.S. concluded killing al-Awlaki was justifiable. 

This week, Rand Paul held up the Senate's confirming of John Brennan's CIA director nomination by demanding the President promise not to kill American citizens' on American soil with drone strikes. Al-Awlaki was brought up then, too. He and his 16-year-old son were both killed by drone strikes in Yemen. The New York Times' Mark Mazzetti, Charlie Savage and Scott Shane just released a thorough, extensively reported story documenting how the Obama administration tracked, found, justified and killed al-Awlaki as he hid in Yemen.

We had already seen parts of the administration's legal justification for killing al-Awlaki, an American citizen on Yemeni soil. We know that, American or not, "senior operational leaders" of al Qaeda or "an associated force" would be targeted by the administration's drones. But we now know how they came to justify letting it happen. 

David Barron and Martin Lederman were the lawyers tasked with justifying targeting al-Awlaki. They had to figure out whether the administration would be able to kill him with a drone strike if they were unable to capture him. Their initial memo boiled down to the fact that al-Awlaki was a bad guy, and bad guys are targets in the war on terror. It was simple enough, but they realized it wouldn't hold up to the kind of scrutiny they knew this decision could face. They started drafting a second memo that they felt would justify killing an American on foreign soil in the war on terror. They stumbled on a law blog discussing "a statute barring Americans from killing Americans overseas," that required them to narrow their focus. Eventually, they found the previously existing court decision they needed to give the Pentagon and C.I.A. the go ahead to target al-Awlaki:

As they researched the rarely invoked overseas-murder statute, Mr. Barron and Mr. Lederman discovered a 1997 district court decision involving a woman who was charged with killing her child in Japan. A judge ruled that the terse overseas-killing law must be interpreted as incorporating the exceptions of its domestic-murder counterpart, writing, “Congress did not intend to criminalize justifiable or excusable killings.”

And by arguing that it is not unlawful “murder” when the government kills an enemy leader in war or national self-defense, Mr. Barron and Mr. Lederman concluded that the foreign-killing statute would not impede a strike.

The administration had they needed. The secret drone base in Saudi Arabia was ready, and they eventually had intel on al-Awlaki's location. Drones were sent out, an American was killed, and the administration has been answering questions about it ever since. If you read anything this weekend, it really should be this story