The killing of Anwar al-Awlaki, the American-born radical Muslim cleric, by a drone strike in Yemen was a minor U.S. victory that raises major questions about the evolving fight against global terrorism.

These include: How important was al-Awlaki? Is the U.S. justified in targeting its own citizens if they are deemed an immediate threat to national security? Is cooperating with the teetering government of Yemeni President Ali Abdullah Saleh in the U.S.’s long-term interests? And does the 2001 congressional authorization to use force against those behind the Sept. 11 attacks extend to groups that had no role in them, such as Yemen’s al-Qaida in the Arabian Peninsula and al-Shabaab in Somalia?

We’ll take those one at a time. Al-Awlaki was a dangerous man with the dubious distinction of landing on the CIA’s “kill or capture” list. His Internet orations stirred popular resentment against the West and inspired isolated actors like Faisal Shahzad, the would-be Times Square bomber. He is thought to have played a role in an effort to blow up an airliner over Detroit on Christmas 2009. And he exchanged e-mails with Major Nidal Hasan, who is accused of killing 13 people at a Texas Army base in 2009.

Although al-Awlaki’s significance in the terrorist pantheon may have been overinflated ― his value as a propagandist stemmed from his American citizenship and fluency in English, not from any influence as a religious thinker ― the U.S. and the world are somewhat safer places without him and the other American killed in the attack: Samir Khan, the editor of al-Qaida’s English-language Internet magazine.

Was the U.S. justified in going after the cleric? There is no question that killing an American risks undermining domestic support for antiterrorism efforts. But we agree with the Justice Department that such strikes are legal and justified to safeguard national security. An enemy combatant is fair game, no matter where he was born.

And Yemen’s president? Saleh, grasping at straws in an effort to stay in power, will no doubt use the operation as an argument for new support from the U.S. He should be ignored. As an ally in the fight against extremism, Yemen has been slightly more reliable than Pakistan, which is faint praise indeed. Any successor government would be just as eager to see al-Qaida in the Arabian Peninsula shut down, and might be a more efficient partner. Even a civil war wouldn’t much change the status quo ― the terrorists in Yemen have long enjoyed a free hand. The last thing the U.S. needs to do is prop up another corrupt dictator.

Finally, debate over extending the war on terrorism beyond Afghanistan and Pakistan had been heating up in recent weeks. It was a well-known secret that, on one side, the Defense Department’s top lawyer, Jeh C. Johnson, argued that the U.S. has a legal right to strike at suspected terrorists in nations unwilling or unable to suppress the threat. He had faced opposition from the top legal adviser to the State Department, Harold Hongju Koh, who reportedly argued that the U.S. could strike only in self-defense ― that is, at people (al-Awlaki included) known to be planning a direct attack on the U.S. homeland.

The question was seemingly resolved in a speech given by National Security Adviser John Brennan at Harvard Law School on Sept. 16. Brennan insisted that the government had the “authority to take action against al-Qaida and its associated forces without doing a separate self-defense analysis each time,” but he said efforts would “focus on those individuals who are a threat to the United States, whose removal would cause a significant ― even if only temporary ― disruption of the plans and capabilities” of the terrorist groups.

This conclusion to claim broad legal authority for the use of force combined with a restrictive policy for actually using it seems to strike the right balance. The administration’s remarkable transparency on counter-terrorism ― explaining in detail the mission that killed Osama bin-Laden (and correcting its initial miscommunications in that account); allowing Brennan to lay out its policy thinking in public; and now divulging specifics on the al-Awlaki strike ― should earn it increased public trust.

The decision to mount a mission to kill a terrorist outside the battlefield, whether a U.S. citizen or not, should always be scrutinized as both policy and military strategy. But those who insist such operations are unambiguously against the law have little to stand on. And in this case, the Obama administration has given us reason to trust its judgment.

(Editorial, Bloomberg)