Yet, from the howls on the left, you would never know that President Barack Obama had won another victory in the war on terror. Even as details of the operation leaked out, critics claimed that our government had "assassinated" an American citizen without due process.
Showing that antiwar fervor is a bipartisan disease, Rep. Ron Paul (R., Texas) immediately went on the offensive. "Al-Awlaki was born here; he is an American citizen. He was never tried or charged for any crimes," declared the Republican presidential candidate. "If the American people accept this blindly and casually that we now have an accepted practice of the president assassinating people who he thinks are bad guys, I think it's sad."
Such fevered accusations echo weightier claims from groups like the American Civil Liberties Union and the United Nations. Representing Awlaki's father, the ACLU sued the Obama administration last year on the theory that the Constitution forbids the government from trying to kill an American citizen for allegedly joining the enemy. According to the ACLU, the United States must arrest Awlaki and bring him home for trial. U.N. officials also issued a report last year suggesting that U.S. drones violate the human rights of suspected terrorists because of the lack of due process.
Last December, however, a federal court in Washington dismissed the ACLU's case. It observed that judges had little ability to intervene in wartime targeting decisions and that Awlaki always had the option of returning home to prove his innocence.
Today's critics wish to return the United States to the pre-9/11 world of fighting terrorism only with the criminal justice system. Worse yet, they get the rights of a nation at war terribly wrong. Awlaki's killing in no way violates the prohibition on assassination, first declared by executive order during the Ford administration. As American government officials have long concluded, assassination is an act of murder for political purposes. Killing Martin Luther King Jr. or John F. Kennedy is assassination. Shooting an enemy soldier in wartime is not. In World War II, the United States did not carry out an assassination when it sent long-range fighters to shoot down an air transport carrying the Japanese admiral Isoroku Yamamoto.
American citizens who join the enemy do not enjoy a roving legal force-field that immunizes them from military reprisal. President Abraham Lincoln confronted this question at the outset of the Civil War.
Under the Ron Paul-ACLU worldview, Lincoln could not order Union troops to fire on Confederates without a trial and should have released them all from military prison because they remained citizens (a view shared, incidentally, by Chief Justice Roger Taney, the author of Dred Scott v. Sandford). What if Union officers could have seized Gens. Robert E. Lee and Albert Johnston at the start of the war?
"Unquestionably, if we had seized and held them, the insurgent cause would be much weaker," Lincoln wrote. "But no one of them had then committed any crime defined in the law" and a court would order them released. Instead, Lincoln concluded, the laws of war must allow the United States to treat its own citizens as enemies when they take up arms in rebellion.
Supreme Court opinions have upheld Lincoln's principle. During World War II, the FBI caught eight German saboteurs trying to sneak into the U.S. and at least one of them was a citizen. On reviewing their military trial and death sentences, the Justices declared: "Citizenship in the United States of an enemy belligerent does not relieve him from the consequences" (Ex Parte Quirin, 1942). "Citizens who associate themselves with the military arm of the enemy government, and with its aid, guidance and direction enter this country bent on hostile acts are enemy belligerents." A nation at war has the right to kill enemy belligerents in war.
The war on terror's unprecedented nature only makes Lincoln's rule even more critical. Al Qaeda has no territory, population or conventional armed forces. It draws its operatives from any country and trains them to covertly infiltrate peaceful societies to launch surprise attacks on civilian targets. If the U.S. were to reserve criminal justice rules for American terrorists, it would only encourage al Qaeda to recruit citizens and ease their path into this country. American al Qaeda operatives would be free from targeting, and efforts to stop them—here or abroad—would require the whole system of warrants, judges, Miranda warnings and lawyers.
Realizing this, the Supreme Court has made clear that the old rules would apply even in this new war. In 2004, it upheld the military detention of Yaser Hamdi, a Saudi Arabian captured during the 2001 U.S. invasion of Afghanistan who had been born in the U.S. "There is no bar to this Nation's holding one of its own citizens as an enemy combatant," the Court's plurality agreed. "A citizen, no less than an alien, can be part of or supporting forces hostile to the United States or coalition partners and engaged in an armed conflict against the United States."
Simply because the Obama administration has the legal right to use force to kill members of the enemy does not mean it must always pull the trigger. It should have good reasons to believe an American has joined al Qaeda. Intelligence reasons favor capturing al Qaeda leaders whenever possible to gain information. But as the Obama administration hastily rushes for the exits in Iraq and Afghanistan, the U.S. will be losing the bases, infrastructure and practice that make possible the high tempo of drone and special-forces operations. The U.S. may be left with no opportunities for capture, and precious few chances to kill.
Mr. Yoo is a law professor at the University of California, Berkeley and a scholar at the American Enterprise Institute. He was an official in the Justice Department from 2001-03, and is co-editor of the recently published "Confronting Terror" (Encounter Books).