WATCH: Retired colonel brutally mocks Trump's '15th Century' understanding of war on CNN

Donald Trump has made a habit of claiming that he knows a lot more about war than many of America's top military brass -- and now one retired colonel has shown us all just how ridiculous that claim is.

In an interview with CNN's Chris Cuomo, Ret. Army Col. Jeff McCausland brutally mocked Donald Trump's conceptions of how to wage war, such as his notion that the military operation in Mosul is a "disaster" because ISIS fighters knew that it was coming. In fact, he said that some of America's most successful military operations came despite the fact that our enemies had broad knowledge of our plans.

"By the spring of 1944, the Germans knew we were going to invade France," he said. "It didn't take a genius. And they were, in fact, preparing beach defenses correspondingly."

McCausland saved special venom for Trump's assertion that America should have invaded Iraq and looted the country of its oil, thus depriving ISIS of its major revenue source.

"It used to be, back in the 15th Century, and before that back in feudal times, but in modern times with the advent of international law, that is no longer the case," he explained.

Even setting aside international law, McCausland explained that the logistics of such an operation would have been absurdly difficult and costly, if not impossible.

"How many soldiers would it take to secure the Iraqi oil fields?" he asked. "Does anyone really imagine that the Iraqi population of 26 million people are going to stand idly by while their country is being looted of the only major resource they have? And even if you can secure those oil fields, notwithstanding how many casualties you're going to take, how many additional troops is it going to take to secure the oil pipelines, so you can get that oil to some place that's going to be exported."

Check out the whole video below.