A case of stupid
Rudy Giuliani argued that "anything is legal in war" in defense of an assertion that America should take oil from Iraq to compensate for America's expenses. The Geneva Conventions prohibit countries from seizing others' property, even in war, but aside from the question of legality, the question remains of how this would be accomplished.
Taking the oil would require military occupation of a large area of Iraq for decades while the oil is extracted and transported. At $45 a barrel, or perhaps less, there is no guarantee that we could recoup the cost of the military occupation required to confiscate the oil.
But the suggestion of taking oil did not include anything as complicated as a military occupation. One of the better known current candidates for U.S. president said, "If we're going to get out, take the oil. If we would have taken the oil, you wouldn't have ISIS, because ISIS formed with the power and the wealth of that oil."
It is hard to imagine what cartoonish vision this well known candidate for president has regarding taking the oil.
Perhaps someone with a pickup could tow a tank that has the capacity of 10,000 oil tanker ships up to the place where the oil comes out of the ground, pump out the oil, have lunch and then drive the oil over to America.
It really isn't a matter of legality, it's a matter of stupidity.