After the United States killed Anwar al Awlaki, a U.S. citizen, in a drone strike last year, people had a lot of uncomfortable questions about why that was OK under U.S. law. On Monday, Attorney General Eric Holder tried to answer them without mentioning the specifics of Awlaki's case. He said extrajudicial killings are legal if they are carried out after due process, clarifying that that doesn't necessarily mean a courtroom. Holder didn't mention Awlaki's name except as an influence on underwear bomber Umar Farouk AbdulMutallab, for whom the DOJ recently secured a life sentence. In his prepared remarks (available in full on the U.S. Department of Justice's website), Holder told a crowd at Chicago's Northwestern University Law School that international law and the U.S. Constitution justified lethal force in the face of an imminent threat, and that while citizens had the right to due process, that didn't necessarily mean a trial by jury:

Some have argued that the President is required to get permission from a federal court before taking action against a United States citizen who is a senior operational leader of al Qaeda or associated forces. This is simply not accurate. “Due process” and “judicial process” are not one and the same, particularly when it comes to national security. The Constitution guarantees due process, not judicial process.

Outside of "due process," Holder outlined four requirements the United States has to follow in order to legally kill a citizen: 

The principle of necessity requires that the target have definite military value. The principle of distinction requires that only lawful targets – such as combatants, civilians directly participating in hostilities, and military objectives – may be targeted intentionally. Under the principle of proportionality, the anticipated collateral damage must not be excessive in relation to the anticipated military advantage. Finally, the principle of humanity requires us to use weapons that will not inflict unnecessary suffering.

Holder's remarks didn't address how Awlaki's case met those requirements. Essentially, he said, we'll have to trust that the government knows what it's doing. That didn't satisfy the ACLU, which criticized the speech in an emailed statement: "Few things are as dangerous to American liberty as the proposition that the government should be able to kill citizens anywhere in the world on the basis of legal standards and evidence that are never submitted to a court, either before or after the fact. Anyone willing to trust President Obama with the power to secretly declare an American citizen an enemy of the state and order his extrajudicial killing should ask whether they would be willing to trust the next president with that dangerous power," Hina Shamsi, director of the ACLU's National Security Project, said in the statement.