The Israeli government has a long history of hunting down its enemies, as it did, famously, with members of Black September, the Palestinian terrorist group that killed 11 Israeli athletes and coaches at the Munich Olympics in 1972. Because of this, most Israelis and much of the world assume that Israel's Mossad spy agency was responsible for the Jan. 19 slaying of Mahmoud Mabhouh, founder of Hamas' military wing, in his Dubai hotel room.

United Arab Emirates police have released details of the killing, including that the hit squad members carried fake British, Irish and German passports, some in the names of Israeli citizens who apparently were unaware that their identities had been usurped. In Israel, most of the public debate has not focused on who did it, or the legality or morality of a targeted killing (which is largely taken for granted), but on the cost/benefit analysis: Was the operation a success because Mabhouh was eliminated, no civilians died and no agent was caught? Or was it a failure because it angered a moderate Arab state and allies, such as Britain, and damaged the government's reputation? The United States has adopted its own program of targeted killings, generally by missiles launched from Predator drones in Afghanistan and Pakistan.

In light of these developments, The Times' Marjorie Miller sought the views of an array of military and human rights lawyers on the legality and legitimacy of targeted killings.

Philip Alston

U.N. special rapporteur on extrajudicial killings

If a foreign intelligence agency was responsible for the killing of Mabhouh, the matter should clearly be classified as an extrajudicial execution. There is no legal justification for the cold-blooded murder of a man who, if alleged to have committed crimes, could have been arrested and charged. Political murders of this type undermine the fabric of international law as well as stoke the fires of conflict.

Amos Guiora

Professor of Law, S.J. Quinney College of Law, University of Utah

I was the legal advisor to the officer in command of the Gaza Strip from 1994-97, and in that capacity was involved in targeted killing decisions. I believed when I served in the Israel Defense Forces, and I believe now, that targeted killings are lawful, predicated on the following caveats.

There must be reliable, valid, viable and corroborated intelligence indicating that the individual intends to commit future terrorist acts. International law does not tolerate revenge-based action. In addition, the decision must meet tests of proportionality, military necessity, alternatives and collateral damage. If the target can be arrested, then that is better, as he can provide valuable intelligence. With respect to collateral damage, the state is obligated to minimize the loss of innocent life in operational counter-terrorism.

When is a person a legitimate target in the context of lawful, preemptive self-defense? There is a requirement for an intelligence picture suggesting significant future action that endangers national security.

There are four categories of legitimate targets in the suicide-bombing infrastructure: the mastermind -- quarterback -- who identifies targets, recruits the bombers and plans the action. The suicide bomber is a legitimate target when he is on his way to commit the terrorist attack. The third category is the person responsible for logistics -- the driver, the person who makes the bomb and facilitates the bombing. He is a legitimate target -- not 24/7, but also not only when engaged in the direct action, meaning he falls in between the mastermind and the bomber. The fourth category is the financier, who is a legitimate target not only when wiring money; but his status needs far further discussion.

I think there is a fundamental difference between drone attacks as presently conducted and targeted killing, for the latter is person-specific whereas the former seems to result in not insignificant collateral damage. I have long advocated person-specific operational counter-terrorism as a means to protect the state and to protect innocent lives.

Kenneth Anderson

Hoover Institution, Task Force on National Security and Law

People who object to targeted killing often seem to have a covert premise that amounts to functional pacifism -- yes, of course you can protect yourselves, but any practicable ways of doing so are, sorry, illegal.

But targeted killing can be an important, discrete, discriminating way of projecting lethal force. Sometimes people mistakenly think that any time you're using force, it must be better to do it in the open, transparent and acknowledged. However, the ability to use force can allow you to take out someone who is a genuine threat without raising the circumstances into open, overt, large-scale war, which could have drastically worse consequences for everyone. The view of the Bush administration was that it didn't make a difference where the strike was because it was a global war on terror. Wherever a target was, that's where you had an armed conflict, even in a legal sense. I'm pretty sympathetic to the Bush administration on national security, but I never thought that was right. War against a nonstate actor has a defined threshold. There has to be ongoing, sustained fighting -- active hostilities. The "global war on terror" did not meet that standard, not in my mind.

On the other hand, "armed conflict" in a legal sense -- and perhaps surprisingly to the non-lawyers -- isn't the only basis for using force in international law. The U.S. and many other countries have traditionally relied on at least the international law of self-defense, permitting uses of force even though the fighting does not rise to the level of an "armed conflict" against a nonstate actor.

In the Dubai hit, based on what I know merely from reading the newspapers, I have no problem with the target being dead. Killing terrorists is fine by me -- and as far as I can tell, my views on that general proposition are no different from Vice President Biden's or President Obama's. The question I have here goes to where Mabhouh was targeted and the apparent use and abuse of passports.

David Kaye

Executive director, International Human Rights Program, UCLA School of Law; former State Department lawyer

My view is that there's no question but that the Dubai operation, if it was Israel, is illegal. Under international law, it's a basic rule that you don't operate in another state without its consent. This is a pretty clear violation of Dubai's sovereignty, presumably without the Emirates' consent; Dubai seems to have a murder case on its hands.

So let's talk consequences: Imagine a Chechen leader, considered extremely threatening by Russia, makes his way to the United States. Russian authorities decide they cannot seek his extradition from the United States back to Russia for any number of reasons, and because he is perceived as such a great threat, Russia mounts an operation to kill this person in the United States. Are we OK with that?

The Dubai killing could be a harbinger of a lawlessness in which any state that sees a threat out there can use force in another state to stop it. International law may not always be enforceable, but it provides a sense of settled expectations about how states are to behave. If Israel did it, and if we consent to its use of force in this situation, then what is the principled response to another state's similar action in the United States or elsewhere?

Forget the hypothetical; in the 1970s, Pinochet had an opposition Chilean figure (and his American assistant) assassinated on the streets of Washington. Just a few years ago, a former Russian security services agent was killed with a radioactive poison in London. Is this the future we want?

Vicki Divoll

Teaches U.S. government and Constitution at the Naval Academy; former CIA lawyer

Reports indicate that Mabhouh's death could be a "hit" by Israeli intelligence or some other government. In the pre-9/11 era, the U.S. would have considered such a targeted killing to be an "assassination," which, under a presidential executive order in effect since the Ford administration, was prohibited if done by U.S. intelligence officers. Indeed, the CIA could not even share intelligence with a foreign intelligence service, including our close allies, if there were any chance it could be used to target and kill an identified terrorist.

Today, that executive order is still on the books. Obviously, however, the Bush and Obama administrations have secretly amended, waived or reinterpreted the ban to allow for the targeted killing by civilian intelligence officers of named terrorists outside of a war zone using armed drones. Reportedly, we have targeted and killed suspected terrorists in Pakistan, Yemen and perhaps elsewhere.

Our moral code and policy pronouncements once reflected an understanding that such treacherous killing was not how a great nation should defend itself -- unless, like Israel, its very survival is at stake. At one time, the United States did not kill in the shadows -- until we became as afraid for our lives as the Israelis have been for decades. But are we really afraid now for our survival as a nation? How can a bunch of thugs reduce us to this?

Michael Walzer

Author of "Just and Unjust Wars"; emeritus professor, Institute for Advanced Study; co-editor of Dissent magazine

Targeted assassinations can be justified when the target is a legitimate enemy who is actively engaged in planning or organizing or carrying out criminal or terrorist activities, and when it's possible to hit the target without killing innocent people. Also, when it's not possible to bring the targeted person to justice in a normal way; when he isn't living in a zone of peace where law and order prevails and policemen make arrests, but when he is living in something more like a zone of war. When those conditions are met, I think this is a legitimate response to international terrorism.

I don't know a lot about Mabhouh. He seems to have been a legitimate target, but there are prudential arguments against hitting him in a country that has been in fact, without anybody acknowledging it, a strategic ally of Israel's -- a semi-friend. And using fake British passports -- I mean, it was done so badly that obviously it shouldn't have been done. The French have this saying: "It was worse than a crime; it was a mistake."

The United States is now committed to targeted assassination as a policy. We have done it sometimes successfully and sometimes with a lot of civilian deaths. It should be the policy of the United States in Afghanistan, and probably in Pakistan too, that after you carry out one of these raids, you should be prepared to defend it. You're using the coercive power of the state in a lethal way, and in a democracy -- in a country committed to the rule of law -- actions of that sort should be subject to some kind of public scrutiny.