Earlier this week, the White House revised its account of the killing of Osama bin Laden, explaining that the Al Qaeda leader was unarmed at the time of his death, contrary to earlier official declarations that he had been wielding a weapon. More details about the military raid on bin Laden’s compound, its scope and conceptualization, are sure to surface in the coming days. But the image of the weaponless, aging Al Qaeda figurehead and founder, shot in the head in his spacious house, has raised some public consternation that the Navy SEALs responsible for the killing acted illegally, or that the United States violated a longstanding Executive Order that bars U.S. employees from engaging in “political assassination.” Human-rights groups and academics have called for inquiries, suggesting that laws may have been broken, or that an “extrajudicial killing without due process of the law” might have occurred. The request for more information about the raid is certainly valid. And the government should be as transparent as possible—especially because, so far, there is little indicating that the Navy SEALs acted outside the boundaries of domestic law.

It is hard to regard Osama bin Laden’s killing as a “political assassination” in the conventional sense. The White House has been insisting that the raid was a military operation, conducted against a military target, and it makes a credible case in doing so. Bin Laden is not a politician, even if his ideology has political aspects to it. He is a declared enemy of the United States, the financier of numerous attacks against American infrastructure and civilians, and the chief signatory of a manifesto that states: “The ruling to kill the Americans and their allies—civilians and military—is an individual duty for every Muslim who can do it in any country in which it is possible to do it.” By his rhetoric and by his actions he has unquestionably proven himself to be a combatant.

Moreover, the raid did not occur while bin Laden was lounging on a beach in Tahiti, or giving a political speech at a rally in Mexico, or meeting with foreign dignitaries in Ottawa. It occurred while he was ensconced in a safe-house in Pakistan—a country that, for better or for worse, belongs to a wider U.S. military theatre of combat in South Asia.

The porous border between Afghanistan and Pakistan, along with the overall complexity of the political relationship between the two countries, has made the conduct of military operations in Pakistan a tactical necessity for soldiers in Afghanistan. For some time now, the U.S. military and the C.I.A. have been operating in Pakistan, with various levels of support from the government there, to hunt down militants and gather intelligence. U.S. Special Forces have fought alongside Pakistani soldiers on several occasions, in the borderland areas, and the American security apparatus has been conducting frequent drone attacks in Pakistani territory—more than a hundred such attacks in 2010 alone. According to a U.S. embassy cable, published last year by WikiLeaks, Pakistan’s Prime Minister told the American ambassador what he thought of the drone program: “I don’t care if they do it as long as they get the right people,” he said. “We’ll protest in the National Assembly and then ignore it.”

In 2007, documents pertaining to the classified Rules of Engagement in Afghanistan entered the public domain, including a summary from 2004 that gave examples of authorized U.S. military incursions into Pakistan. For instance, the document stated, the “hot pursuit” of Al Qaeda militants into Pakistan was permitted, though the pursuit from one country to the other had to be “continuous and uninterrupted.” Also permitted was a direct action “against The Big 3,” a reference to bin Laden, Ayman al Zawahiri, and Mullah Omar, the Taliban’s supreme leader. Finally, to add even greater flexibility, the document permitted cross-border incursions, apparently based on unforeseen circumstances, at the discretion of the Secretary of Defense. One caveat the document put upon these actions was “geographic limits.” It stated: “General Rule: penetrate no deeper than 10km.” Such limits, the language suggests, were not sacrosanct.

It’s hard to say what the Rules of Engagement were at the time of the bin Laden raid; the rules change in their details frequently, but their overall structure tends to remain fairly constant. If you can accept that Pakistan is a legitimate U.S. military area of operation, then the second question emerges: was the military’s targeting and killing of bin Laden consistent with its own legal doctrine?

When using lethal force within a field of combat, the military’s Rules of Engagement have historically defined two kinds of acceptable targets. The most common are known as “combat-based targets.” In a long article that I wrote for The New Yorker in 2009, titled “The Kill Company,” I described them as:

People who act in a hostile manner or display hostile intent. Hostile actions are easy to identify. (If a cabdriver fires a rifle at a soldier, he instantly becomes a combatant.) Establishing hostile intent is harder. (If a cab is racing toward a soldier, is the driver’s intent hostile, or is he drunk?) Whenever a soldier uses force, the rules say, his reaction must be proportional to the threat. In part because judging intent and proportionality are subjective, the Army scrutinizes every incident in which one of its weapons is discharged.

Had bin Laden been armed and shooting at the time of the raid, he would have very easily met the standard of a combat-based target, and could legally have been killed. But as Jay Carney, the White House spokesperson, said the other day, “Resistance does not require a firearm.” Bin Laden could have been legally killed if he were holding a weapon and not firing—or if he were holding no weapon at all. Any soldier seeing bin Laden and recognizing him could make a reasonable assumption that he had “hostile intent.” After all, Al Qaeda bodyguards were nearby, and they were shooting at the Navy SEALs to defend him. “This is a guy who’s extremely dangerous,” John B. Bellinger III, legal counsel at the National Security Council and State Department in the Bush Administration, told the New York Times. “If he’s nodding at someone in the hall, or rushing to the bookcase or you think he’s wearing a suicide vest, you’re on solid ground to kill him.” Military law tends to recognize that soldiers must confront myriad, and potentially lethal, ambiguities amid the heat of battle.

That being said, the legality for killing bin Laden is not especially dependent upon his behavior during the raid because, in his case, an alternate (and more relevant) aspect of the Rules of Engagement applies. There is no military circumstance where an Al Qaeda operative of bin Laden’s stature could merely be a “combat-based target” in the way a low-level insurgent at a roadside checkpoint would be, because he is also a high-value target, and his status as such matters. In 2009, I also described why: