Five Iranian officials with ties to Iran's nuclear or military establishment have been killed, or died under mysterious circumstances, in the last month. It is widely assumed that this is part of an Israeli campaign against Iran developing nuclear weapons (in principle, Israel neither confirms nor denies such allegations). Would such attacks be a legitimate and prudent response to such a threat?

No. Targeted killings may be legal in international law under certain circumstances, and morally acceptable when employed against law-breakers or in wartime. Many nations, including the United States, have deliberately targeted officials or leaders seen as mortal enemies. But engaging in competitive assassinations with Iran is not a road that Israel should be going down, on simple grounds of effectiveness and prudence.

In perspective, killing an enemy's leaders has a long historical pedigree. Medieval Italian city-states even occasionally employed official assassins to take out troublesome opposing statesmen. As international law become codified in recent centuries, such actions generally fell under the laws of war, meaning that there had to be a just cause for this act of warfare and that it met the standard criteria of distinction (between military and civilian), proportionality, humanity, and military necessity.

War is in fact permissible targeted killing on a broad scale. But it has been often extended beyond the battlefield. There was no legal or moral objection during World War II when the U.S. forces identified the airplane carrying Admiral Yamamoto, planner of the Pearl Harbor attack, and shot it down.

But does this extend further on the home front, to civilians who may be engaged in hostile activity but are not part of the military? A case can be made that individuals carrying out acts of war can expect that war will be waged against them in response. The fact that they do not wear a uniform gives them, in some respects, even less protection under international law.

Thus targeted killing of leaders of paramilitary movements -- Hamas, for example -- is arguably legal, though it may not be effective or prudent. The targeting of Iranian scientists raises more doubts: are they really "enemy combatants"? But even if legally justifiable, there remains the critical question of "military necessity," read here to mean: is this really an effective way of dealing with the threat?

Targeted killings of terrorist leaders ("decapitation" is the term of art) have not demonstrably reduced the strength and threat of such movements. A new leader, often worse or more effective that the decapitated figure, simply takes over. A martyr is created, popular rage and support increase, and the leadership finds more effective ways to hide.

Above all, the incentive to retaliate prevails; reprisals of one kind or another are almost certain. In the Iranian case, the aggrieved party is a national government with considerable resources and options at its command. Israeli targets, officials or simply citizens, are spread across the globe in very vulnerable positions. The only question is when and where the near certain retaliation will come.

There are options to assassinations as a fallback strategy. There are other forms of covert action less likely to devolve into a game of tit for tat. There is coalition-building with other nations threatened by Iran. There is, above all, return to the nuclear deal that kept Iran months or years, rather than weeks, away from having enough fissile material for its first bomb.

Perspective

Perspective 75. Targeted Killings: Legal…