Retired Army Lt. Gen. Mark Hertling says he had “a visceral response” to some of the rhetoric Donald Trump unleashed during the most recent Republican debate.

But the statement that really concerned him, Hertling told CNN’s Chris Cuomo on Monday, came when Trump told debate moderator Bret Baier that there’s no way U.S. service members would refuse to follow his orders.

“They won’t refuse,” Trump said during Thursday’s debate on Fox News. “They’re not going to refuse me, believe me. If I say do it, they’re going to do it. That’s what leadership is all about.”

Hertling forcefully disagreed, calling the Republican front-runner’s management style “toxic leadership.”

“Somebody needs to remind Mr. Trump that the military is not his palace guards,” Hertling said. “They take an oath to defend the Constitution of the United States against all enemies foreign and domestic. They also abide by the rules — not only of the uniform code of military justice, the UCMJ — but they also abide by the U.N. mandate against torture and the Geneva Convention protocols against torture.”

“We do not do this,” he added. “It is not within our purview.”

Hertling retired in 2012 as a three-star general and commander of all U.S. Army forces in Europe. He previously commanded an armored division in northern Iraq. His comments came Monday during a broader discussion with New Hampshire state Rep. Al Baldasaro, a military veteran and ardent Trump defender.

On the campaign trail and in debates, Trump has offered conflicting statements about his views on torture.

On Friday, Trump appeared to walk back his remarks from the previous night’s debate, saying he would not force a military officer to violate the law. If elected, he said, he will be bound by laws “just like all Americans” and will meet those responsibilities.

He noted that he feels strongly about the need to kill terrorists who aim to strike the United States.

“I will use every legal power that I have to stop these terrorist enemies,” Trump said. “I do, however, understand that the United States is bound by laws and treaties, and I will not order our military or other officials to violate those laws and will seek their advice on such matters.”

Trump previously told a South Carolina retirement community that he supports waterboarding and similar interrogation techniques because “torture works” when it comes to extracting vital information from terrorists.

Deeming waterboarding “torture,” the Obama administration discontinued its use during his first term in office. As The Post’s Jenna Johnson noted, proponents of the controversial practice avoid labeling it as torture, which would violate various international laws and treaties.

Trump has not only pledged to reinstate waterboarding, he has even promised to introduce other methods of interrogation that are “so much worse” and “much stronger.”

“Don’t tell me it doesn’t work — torture works,” Trump told the Sun City retirement community. “Okay, folks? Torture — you know, half these guys [say]: ‘Torture doesn’t work.’ Believe me, it works. Okay?”

Those remarks were criticized by former CIA director Michael Hayden during an appearance on HBO’s “Real Time with Bill Maher.” Hayden told Maher that he believes there is a legitimate possibility that the U.S. military would refuse to follow orders given by Trump if the candidate’s language didn’t evolve.

“I would be incredibly concerned if a President Trump governed in a way that was consistent with the language that candidate Trump expressed during the campaign,” said Hayden, who also headed the National Security Agency from 1999 to 2005.

During his appearance Monday on CNN, Hertling didn’t reference Hayden’s comments, but he did say there are no indications that torture works.

He knew, he said, because he’d run interrogation facilities in combat.

“It’s used by individuals to generate revenge or frustration or oppose an authority, but it does not generate information,” Hertling said. “There are much better ways to get information through proper interrogation techniques.”

“And the military,” he added, “has never done enhanced interrogation techniques.”

This is not the first time Hertling has tangled with Trump over foreign affairs and the billionaire businessman’s leadership style. In July, Trump told CNN’s Anderson Cooper that he’s “a better general” than Hertling, during a conversation about keeping terrorists from infiltrating Iraq’s oil fields.

Hertling subsequently said Trump’s “simplistic analogies” show that he lacks a firm grasp of foreign affairs.

“He may be a very good businessman, but the art of soldiering is a profession,” Hertling said. “I’m not sure he understands the science and the art of soldiering and the connection of military strategy with national security strategy.”

The retired Army commander added: “He certainly doesn’t understand the complexity of what’s going on in Iraq and the Middle East.”