After announcing that Osama bin Laden had been killed by a team of commandos, President Obama declared, “Justice has been done.”

But not everyone — delighted and relieved as they may have been that bin Laden could no longer rain terror down on an anxious world — was convinced that the manner and circumstances of his death were just. There’s been a lot of discussion about the legality of shooting bin Laden without benefit of a trial.

The U.S. Constitution guarantees that justice will be meted out after the accused — no matter how heinous his crime — has been found guilty in a court of law. Since 9/11 we have been debating whether terrorists are criminals (to be tried in civil court) or military combatants (to be tried in military tribunals). In either case, we are (mostly) agreed that they should be tried, not summarily executed. This respect for the rule of law is quintessentially American. It defines who we are. Or who we were.

In the last decade the rules have changed and so have the laws. To defend ourselves in an endless war against a faceless enemy, we have abandoned principles long held dear and engaged in practices our parents and grandparents wouldn’t recognize. To be sure, we were never perfect — the My Lai massacre comes to mind — but until now, no one justified torture or prettied it up as Orwellian “enhanced interrogation.” We had no “rendition” — the shipping of prisoners off to “black sites,” overseas dungeons in places that have no inconvenient laws that forbid torture and protect the rights of prisoners.

The captives at Guantánamo are not the only ones stripped of their rights. We, the American public, have forfeited our privacy and surrendered the sanctity of our homes by authorizing the government to eavesdrop on every telephone call, scan every email and search private records and property, all without the owner’s knowledge or consent. It’s useful to remember, however, that without a vast electronic net of surveillance and before the government was empowered with unprecedented authority, the signals of the impending 9/11 attack were received, noted and dismissed.

When I heard President Obama say that bin Laden had been killed, I reacted with satisfaction, relief and an atavistic sense of joy. I don’t normally rejoice in someone’s death and I oppose the death penalty. But I don’t doubt that the man who devised such atrocious ways to maximize fear, suffering and death deserved retribution — in fact, I believe he should have experienced some of what he imposed on his victims. In complete defiance of my principles, I was always convinced that bin Laden should never be captured and brought to the United States because of the reprisals — kidnappings, beheadings, suicide bombings — that would surely ensue to obtain his release. Though deprived of a martyr’s tomb, bin Laden continues to menace from his watery grave on the posthumous audiotape released by Al Qaeda.

And still . . .

If we make an exception for bin Laden, if we cross that line, Glenn Greenwald asks, where do we stop? Why not Khalid Sheik Mohammed, the alleged mastermind of 9/11? What about Al Qaeda’s second- and third-in-command?

We may all agree that the death of bin Laden was long overdue and the entire world is immeasurably better off without him, but Greenwald reminds us that high-ranking Nazis — in the same class as bin Laden, I would argue — were tried at Nuremberg. Greenwald cites the opening statement of lead prosecutor Robert Jackson:

That four great nations, flushed with victory and stung with injury stay the hand of vengeance and voluntarily submit their captive enemies to the judgment of the law is one of the most significant tributes that Power has ever paid to Reason.

There is however a difference. Though we were stung with injury, we weren’t flushed with victory. The world has changed much in 65 years: our enemies no longer wear uniforms, and they use any means to attack us anywhere. They operate with no holds barred.

So, was the killing legal?

“It is one thing to argue that capture and trial would have been preferable, another entirely to argue that the killing was illegal,” writes Adam Serwer.

A trial is necessary, says Michael Moore, to establish “a very public and permanent historic record of the crimes against humanity,” a record to teach our grandchildren “so that they would never forget these horrors and how they were committed.”

Andrew Sullivan takes another tack, asserting that “we are morally permitted to defend ourselves with violence” against someone “who has orchestrated the mass killing of thousands [and] has declared war on us.” Robert Chesney and Juan Cole agree — the SEALs’ raid was in keeping with the U.N. Charter, which recognizes the right of a state to defend itself from attack.

“Violence can be a form of justice, and justice occasionally requires acts of violence,” concurs Thomas Nachbar, though, he insists, the two should never be confused:

Why bother making the distinction? Because we can act according to our principles only if we can think clearly about them, and we can think clearly about them only if we talk clearly about them. And our principles — those worth fighting and dying for — are what separate us from the likes of Osama bin Laden, not the ability to kill people thousands of miles away.

Maintaining that bin Laden was lawfully killed, Sullivan draws a clear line “between an enemy at large where he can still inflict casualties and an enemy already detained, where he cannot. … the ability to make distinctions is what makes a civilization in a fallen world, where evil endures and also seduces.”

Has Al Qaeda seduced us into believing that torture and assassination are justifiable? Democracy is precious, but it is also fragile. If to protect ourselves we must voluntarily relinquish the rights we fought to establish and preserve, has Al Qaeda won? Has it seduced us into believing that we can be safe only in a police state that monitors our movements, records and words with ubiquitous hidden eyes and ears? Does anyone believe that the National Security Agency will ever cut back its electronic surveillance or dismantle the vast structures that store the data culled from every aspect of our lives? It’s a slippery slope.

President George W. Bush declared two American citizens “enemy combatants,” thereby justifying their detention in military prison without being charged or given access to an attorney in violation of the constitutional guarantees of habeas corpus and a speedy and public trial. Will more American citizens be “disappeared”?

I don’t know the answer to this existential dilemma — whether to be safer at the cost of renouncing certain rights and a measure of freedom or to preserve our open society at the risk of missing signs of an impending attack. For now, however, we need to be very clear about the choices we are making and consider how they change a way of life we can no longer take for granted.