Can U.S. nuclear strike planners and executors be prosecuted for war crimes? Short answer, yes. And the planners are more vulnerable to prosecution than world leaders, such as President Donald Trump.

A preliminary question, of course, is what would constitute an illegal nuclear strike order. It is fairly clear that any use of nuclear weapons to achieve military objectives that conventional weapons can otherwise achieve would be illegal.

The reason is that the nuclear option would violate principles of the law of war, or what's called humanitarian law, by causing indiscriminate and disproportionate loss of life and superfluous injury, since nuclear weapons are far more catastrophic than conventional weapons. If conventional weapons could achieve the same military objectives, then any order to use nuclear weapons instead would be manifestly illegal, leading to allegations of war crimes.

This Nov. 29, 2017, photo provided by the North Korean government shows what the North Korean government calls the Hwasong-15 intercontinental ballistic missile, at an undisclosed location in North Korea. (Korean Central News Agency)

But heads of state like Trump are generally immune from prosecution, at least while they remain in office, even for serious violations of international law like war crimes and crimes against humanity.

However, the whole reason heads of state enjoy immunity is that the state would be unable effectively to represent itself in its dealings with other states if these individuals were stuck in foreign states' docks. Thus high-ranking members of the U.S. Strategic Command and other planning bodies likely fall outside the scope of immunity, and the farther down the chain one goes, the less immunity applies. In turn, only heads of state and perhaps other extremely high-ranking officials would have immunity.

But where could these planners and executors be prosecuted? One option would be in U.S. domestic courts or military tribunals, especially if there is a change in administration. Another option would be foreign tribunals. Because war crimes are subject to what's called universal jurisdiction, any nation in the world may prosecute the perpetrators of these crimes. This is not just theoretical or academic. The practice of universal jurisdiction has spiked in recent years when it comes to serious violations of international law, such as torture, crimes against humanity and certain acts of terrorism.

Nuclear strike planners have a duty under international and domestic U.S. law to reject illegal nuclear strike orders. If they do not, they can be held liable in both domestic and foreign courts. Immunity will not shield them from prosecution.

Anthony J. Colangelo is a law professor at Southern Methodist University and a senior associate at the Nautilus Institute for Security and Sustainability. He wrote this column for The Dallas Morning News. Email: colangelo@smu.edu

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