The Navy SEALs who killed Osama bin Laden in his Pakistan compound yesterday acted within the full authority of both international and domestic law, according to US legal analysts.

As the operational leader of Al Qaeda in an ongoing conflict with the United States, Mr. bin Laden was a legitimate military target to be captured or killed at any time under the law of war, these analysts said.

“We could have killed him even if he was trying to run away. He was a lawful target,” said Scott Silliman, a law professor and executive director of the Center on Law, Ethics, and National Security at Duke University.

Rather than an unlawful assassination, the Navy SEALs’ assignment to “capture or kill” bin Laden was a fully authorized military mission. Bin Laden was a combatant in the war, as were members of the SEAL team.

“When all the layers are peeled away from a tactical perspective, the government did everything by the book,” said Stephen Vladeck, a law professor at American University’s Washington College of Law.

In 1996, bin Laden himself declared war on the US, issuing a religious decree authorizing the murder of American citizens wherever they might be found.

Congress responded after the 9/11 attacks with passage of the 2001 Authorization to use Military Force. The measure empowers the president to “use all necessary and appropriate force” against nations, organizations, or individuals who played a role in the 9/11 attacks. The law was written specifically with bin Laden in mind.

In addition, Presidents Bush and Obama signed secret executive orders authorizing kill-or-capture missions by the Central Intelligence Agency and the military’s special forces.

Some denounce 'execution'

Although the US has received widespread support and praise for the bin Laden operation, a handful of critics are denouncing it as an unlawful “execution.”

These critics say bin Laden deserved the due process rights of a trial before facing capital punishment for his alleged crimes.

Others disagree. “Osama bin Laden was a criminal responsible for heinous terrorist attacks that cost the lives of thousands of innocent people,” said a statement issued by the European Commission and European Council. “His death makes the world a safer place and shows that such crimes do not remain unpunished.”

The statement continues: “This is a major achievement in our efforts to rid the world of terrorism.”

United Nations Secretary-General Ban Ki-Moon offered a similar assessment. “The death of Osama bin Laden … is a watershed moment in our common global fight against terrorism,” he said.

“Personally, I am very much relieved by the news that justice has been done.”

Abbottabad, Pakistan: 5 things to know about where Bin Laden died

Although full details have not yet emerged, initial reports are that bin Laden was shot and killed in an exchange of fire near the end of the 40-minute military operation. It is not clear whether bin Laden himself was firing a weapon at US personnel.

If bin Laden was shooting, that offers US forces another justification for the use of lethal force. Like police officers confronting an armed suspect, law enforcement officials are authorized to use deadly force to defend themselves and others.

The same justification could apply to the bin Laden operation, said Jonathan Hafetz, a law professor at Seton Hall University School of Law.

“Even if Osama bin Laden was outside [a zone of] armed conflict, did not have a continuous combat function, and was not subject to targeted killing [under the law of war], the killing could be a justified use of lethal force under various possible scenarios, as many police shootings of criminal suspects are,” Professor Hafetz said.

'Capture or kill' was significant

There were other advantages to sending US forces in. International reaction to the bin Laden operation might have been quite different if the US had relied on hellfire missiles launched from drones into the windows of the bin Laden compound.

The use of missiles fired from a distant control center would likely have inflamed a raging debate among international legal scholars over the use of heavily-armed drones to carry out targeted killings both in Afghanistan and Pakistan, said Professor Vladeck.

It is also significant, he said, that the mission was described by President Obama as “capture or kill.” By contrast, when missiles are deployed, “capture” is generally not an option.

Atmospherics matter, he said. “There is just something different about sending armed forces in military uniforms with the US flag on their sleeve to conduct this kind of operation,” the professor said.