Democratic presidential nominee Hillary Clinton and her Republican opponent Donald Trump answered questions on national security and foreign policy Sept. 7 during a "commander-in-chief forum" on NBC News. (Video: NBC News/Photos: Melina Mara/Post, Mike Segar/Reuters)

There was a very weird thread worth picking out of Donald Trump’s comments during NBC’s “Commander-in-Chief Forum” on Wednesday night. Over the course of a brief back-and-forth with moderator Matt Lauer, Trump shrugged at a past comment that he knew more about the Islamic State than America’s generals, disparaged those generals by saying they'd been “reduced to rubble,” suggested that his plan to defeat the Islamic State — long something he said was a secret — would instead be formulated with help from top generals and, ultimately, casually indicated that he might just fire most of the generals anyway.

Of the many ways in which Trump contradicted himself or betrayed a misunderstanding of how things work, this rapid evolution was hardly the most egregious example. There was, for example, his return to the idea that America should have purloined Iraq’s oil after ousting Saddam Hussein. He once suggested this should have happened to provide revenue to wounded soldiers; he now argues it would have blocked the rise of the Islamic State (or ISIS, as he calls the group).

“If we would have taken the oil, you wouldn’t have ISIS, because ISIS formed with the power and the wealth of that oil,” Trump told Lauer. How would we take it? “Just we would leave a certain group behind and you would take various sections where they have the oil,” he replied. One might wonder if we couldn’t just, you know, guard the oil on behalf of the Iraqis to curtail the Islamic State, if we’re putting people around the oil anyway? Well: “It used to be to the victor belong the spoils,” Trump said. But lest you think that implies that we — meaning advocates of the conflict such as Hillary Clinton — were somehow victorious in Iraq, we weren’t. “Now, there was no victor there, believe me. There was no victor," Trump said. “But I always said: Take the oil.” So it’s not “to the victor belong the spoils,” then, but “take the spoils of a sovereign nation for reasons that may vary over time.”

But, again: Let’s set that aside. Let’s focus on the generals.

The way the promotional structure of the United States military works is not complicated. Generals are not selected by being hired from the private sector thanks to their thorough LinkedIn profiles. Instead, they slowly rise through the ranks. Here is an interesting thread outlining what it takes to be promoted to general in various branches of the armed forces. The short version is that it’s the culmination of a flawless decades-long career within one branch that rides heavily on personal and professional chance. The long version is longer than that.

Trump offered his views on America’s top generals to Lauer over the course of a few questions.

“ ‘I know more about ISIS than the generals do. Believe me,’ ” Lauer quoted Trump as saying, then asked: “Was that the truth?”

“Well, the generals under Barack Obama and Hillary Clinton have not been successful,” Trump replied. “I think under the leadership of Barack Obama and Hillary Clinton, the generals have been reduced to rubble. They have been reduced to a point where it’s embarrassing for our country.”

“Have you lost faith in the military commanders?” Lauer pressed a bit later.

“I have great faith in the military. I have great faith in certain of the commanders, certainly,” he said. “But I have no faith in Hillary Clinton or the leadership.”

An audience member asked Trump for details on his promise to rapidly defeat the Islamic State. This is where Trump started talking about the oil, so Lauer brought it back to the terrorist group. “You very often say, I’m not going to give you the details because I want to be unpredictable,” he said. “But yesterday, you actually told us a little bit about your plan in your speech. You said this. Quote: ‘We're going to convene my top generals and they will have 30 days to submit a plan for soundly and quickly defeating ISIS.’ So is the plan you’ve been hiding this whole time asking someone else for their plan?”

“No,” he replied. “But when I do come up with a plan that I like and that perhaps agrees with mine, or maybe doesn’t — I may love what the generals come back with.”

“If I win, I don’t want to broadcast to the enemy exactly what my plan is,” Trump added. “And let me tell you, if I like maybe a combination of my plan and the generals’ plan, or the generals’ plan, if I like their plan, Matt, I’m not going to call you up and say, ‘Matt, we have a great plan.’ ”

“But you’re going to convene a panel of generals, and you’ve already said you know more about ISIS than those generals do,” Lauer rebutted.

“Well, they’ll probably be different generals, to be honest with you,” Trump replied, then boasting of having the endorsement of 88 former military leaders. (As Lauer noted, that’s a number that is a bit lower than what Clinton claims.)

Trump offered that line about “different generals” casually, but it’s not an insignificant claim. As president, Trump’s ability to overhaul the leaders of the military is limited. As commander in chief, he can remove generals from positions but he “doesn’t enjoy Donald Trump-like powers to summarily fire service members,” as Brian Palmer explained for Slate back in 2010 (clearly when “The Apprentice” was still on the air). When President Obama relieved Army Gen. Stanley McChrystal of his command in 2010 after McChrystal gave some ill-advised comments to a reporter, McChrystal retained his rank as a four-star general, until he decided to retire. Trump could seek the counsel of other members of the military’s leadership, but he can’t simply clean house or bring in people from the outside.

It’s not clear that Trump recognizes such nuances, though. He has in the past seen the line between the military and the commander in chief as blurrier than it is in reality. During a debate in March, Trump was asked by Fox News’s Bret Baier what he would do if the military refused to carry out his orders to commit acts of torture or target civilians.

“They won’t refuse,” Trump replied. “They’re not going to refuse me. Believe me.”

Buried in all of this are competing instincts: Trump’s lack of interest in being wrong and his great interest in being the boss. He threatens to oust top leaders of the military for little other reason than they were in positions of authority under Obama. While his prepared comments from Tuesday suggested that he would seek the counsel of service members who’d committed decades to protecting America’s interests, he tossed that to the side in favor of not being embarrassed by Matt Lauer, insisting that he still did have his own secret plan. Probably one that involves oil.

Bear in mind, the president’s role as commander in chief was the primary focus of the town hall. It’s what Trump was there to talk about. And, for good or bad, he talked about it.

Update: A retired major general from the Army Reserve emailed to note that “generals” is a broad group that includes one- and two-star generals — positions attained by promotion — and three- and four-star generals, who receive appointments.