War crime in the making?

With threats that "entire civilization" will disappear, along with prior warnings that US forces could target and destroy bridges and energy infrastructure across Iran, United States President Donald Trump is announcing actions so far-reaching that some military law experts believe they could constitute a war crime.

After Iran showed no signs of accepting Trump's ultimatum to open the Strait of Hormuz by the end of the day, the US president announced on his social network: "The entire civilization will disappear tonight, and it will never be brought back. I don't want it to happen, but it probably will."

Brian Finucane, a former legal adviser to the US State Department who now works at the International Crisis Group, told Reuters that Trump's statements "could reasonably be interpreted as a threat to commit genocide" under US and international law.

The US president said on Monday that US forces could target every bridge and energy infrastructure in Iran in a threat so sweeping that it appeared to disregard the consequences for civilians, prompting Democrats in Congress, some United Nations officials and military law experts to assess how such attacks would violate international law.

Trump's final actions are often milder than his sweeping rhetoric at a given moment, but his warnings about attacks on civilian targets in recent days have been unequivocal, the Associated Press agency points out.

A spokesman for United Nations Secretary-General Antonio Guterres warned on Monday that attacking such infrastructure is prohibited by international law.

“Even if certain civilian infrastructure could be characterized as a military objective,” said Stéphane Dujarric, “an attack would still be prohibited if it carries a risk of ‘excessive collateral damage to civilians.’”

Rachel VanLendingham, a professor at Southwestern Law School who served as a legal advisor to the U.S. Air Force, told the AP that civilians would likely be killed if hospitals and water treatment plants were left without power.

"What Trump is saying is: We don't care about precision, we don't care about the impact on civilians, we will simply destroy Iran's entire power generation capacity," said the retired lieutenant colonel.

Trump said on Monday that he was “not at all” concerned about the possibility of committing war crimes while continuing to threaten destruction. He also warned that any power plant “will burn, explode and never be usable again.” “I hope I don’t have to do that,” Trump added.

Asked for additional comment on Monday, White House spokeswoman Anna Kelly said that "the Iranian people welcome the sound of the bombs because it means their oppressors are losing."

Politiko reported, citing informed sources, that the Pentagon is expanding the list of Iranian energy facilities it may target, including those that supply fuel and energy to both civilians and the military, which could serve as a sort of circumvention in the event of war crimes charges for attacks on essential infrastructure.

Military planners are reviewing the list, two defense officials said, as U.S. and Israeli warplanes, after five weeks of nonstop strikes on military targets, search for new targets and as U.S. ground forces arrive in the region. The dual-purpose nature of the targets, officials said, would make them legitimate targets.

There is a dispute over where to draw the line between military and civilian targets, such as water desalination plants, which could be considered legitimate targets because military forces also need water.

On Easter Sunday, Trump threatened in a profanity-laced tweet that Iran would face "power plant day and bridge day rolled into one," warning that it would "live in hell" if the strait was not reopened.

“This strikes me as a clear threat of unlawful action,” said Michael Schmidt, professor emeritus at the U.S. Naval War College and professor of international law at the University of Reading in the United Kingdom.

A power plant can be a legitimate target under the laws of armed conflict if, in addition to civilians, it supplies electricity to a military base, Schmidt said. However, an attack must not “cause disproportionate harm to the civilian population, and everything must be done to minimize that harm.”

Harm does not mean discomfort or fear, added Schmidt, who has trained military commanders. But it does include severe psychological distress, physical injury or illness. Schmidt said military commanders should consider alternatives, such as targeting a substation or power lines that supply the base with electricity, before destroying an entire power plant.

“If you look at an operation and you see that you have a legitimate military objective, but that the attack would harm civilians, and you think, ‘Wait, this is too much,’ then you should stop,” Schmidt said. “If you’re having second thoughts about firing that shot, don’t fire it.”

Politico points out that Defense Secretary Pete Hegseth last year drastically reduced Pentagon offices that help select military targets and prevent harm to civilians, which could mean weaker oversight of such matters.

Hegseth decided to reduce the number of employees working on the issue from 200 to less than 40. The dismissed officers helped military commanders select targets to spare civilian lives, and after the attacks were carried out, they investigated their consequences to better protect civilians in the future.

Hegsett announced last month that he would further reduce the number of lawyers who advise commanders on the legality of operations, known as military court advocates. He had already fired Army, Navy and Air Force lawyers in the early days of his administration.

Even if they might technically be justified under the laws of war, attacks that harm civilians could backfire on the United States in the long run, VanLendingam said.

“There’s a lot of violence that can still be justified as lawful, but lawful can still be horrific,” VanLendingham said. “How far did it get us in Iraq? How far did it get us in Afghanistan? How far did it get us in Vietnam?”

Trump's rhetoric, she said, risks spreading fear among ordinary Iranians and sending a message that the US does not care about their well-being. Iranian leaders could use it as propaganda to create and entrench resistance, which would contribute to a longer and more difficult war.