International law permits attacks on energy plants and other ostensibly civilian targets only if it is determined that they primarily support military activity. Tom Dannenbaum, a professor at Stanford Law School, said Trump’s statements indicated otherwise.

“The reference to the stone age indicates that objects would be targeted seemingly because they contribute to the viability of a modern society in Iran, which is completely unrelated to the question of contribution to military action –the necessary condition for targeting in war,” he said.