Republican presidential candidate Donald Trump speaks at a rally at Macomb Community College, Friday, March 4, 2016, in Warren, Mich. (AP Photo/Carlos Osorio) (Carlos Osorio/AP)

Donald Trump promises that if Americans send him to the White House, he’ll bring back waterboarding — and techniques that are “a hell of a lot worse.” Why? Because “torture works,” he claims, and even “if it doesn’t work, they deserve it anyway.” That’s not Trump’s only bright idea for U.S. counterterrorism policy. He’d also “bomb the hell out of ISIS,” and he favors targeting the spouses and children of Islamic State fighters, too, since “with the terrorists, you have to take out their families.” That kind of rhetoric from the GOP front-runner has rightly alarmed the foreign policy establishment, prompting an open letter this past week from an array of Republican advisers opposing Trump.

Former CIA director Michael Hayden, who also served as a four-star Air Force general and the director of the National Security Agency, sees a remedy: The military would save us from Trump’s excesses if he somehow gets elected. “If any future president wants . . . to waterboard anybody, he better bring his own bucket,” Hayden has said. The Pentagon would never let him get away with war crimes: “The American armed forces would refuse to act,” he told HBO’s Bill Maher recently. “You are required not to follow an unlawful order.”

Hayden’s right that any presidential order to use torture or deliberately target civilians would be illegal. Under international and U.S. law, both are grave crimes, punishable by imprisonment or, under U.S. law, death. He’s also right that military personnel have no duty to obey unlawful orders.

But don’t count on the Pentagon to stop President Trump. The billionaire himself, asked at a Republican debate Thursday night what he would do if the military refused to obey his orders, seemed aware of that: “They won’t refuse. They’re not going to refuse me. Believe me. . . . If I say ‘Do it,’ they’re going to do it.” (On Friday, he said he wouldn’t order troops to violate the law.)

Unfortunately, recent history suggests that he’s right. Military resistance is no safeguard against a future president — Trump or anyone else — who’s determined to have his way.

Laws can be manipulated, and they can be changed, especially when a president wants them manipulated or changed. The U.S. military has a strong rule-of-law culture, but it also has a strong commitment to civilian control of the armed forces. Generally speaking, that’s good, but it also means that officers rarely respond with a flat-out “No” when senior civilian officials start playing fast and loose with the law. The armed forces have a duty to disobey manifestly unlawful orders, but when top civilian lawyers at the White House and the Justice Department overrule the military’s interpretation of the law, few service members persist in their opposition.

Think back to the first few years after the 9/11 attacks. The Pentagon initially planned to treat Taliban and al-Qaeda prisoners in accordance with the rules laid out in the Geneva Conventions, but the White House considered this inconvenient. (Under those rules, prisoners can’t be detained secretly and with no review process, and they most definitely can’t be waterboarded.) So the White House found some unusually compliant Justice Department lawyers, and by January 2002, the department’s office of legal counsel was instructing the Defense Department that Geneva Convention protections did not apply to Taliban or al-Qaeda fighters.

Colin Powell, the George W. Bush administration’s secretary of state and former chairman of the Joint Chiefs of Staff, objected immediately, as did several top active-duty military officials. The Justice Department’s position would “reverse over a century of U.S. policy and practice in supporting the Geneva conventions,” Powell argued, making the United States “vulnerable to domestic and international legal challenges” and creating a risk of criminal prosecution for American officials and troops.

The White House ignored such protests; then-White House counsel (and later attorney general) Alberto Gonzales asserted in a Jan. 25, 2002, memo to President Bush that the position“preserves flexibility” for the White House and “reduces the threat of domestic criminal prosecution under the War Crimes Act.” His logic: If the Geneva Conventions don’t apply, then U.S. officials can’t violate them.

The same legal sleight of hand occurred with interrogation practices. Before 9/11, no courts or serious legal scholars argued that waterboarding was anything other than torture or that torture was anything other than illegal. But after 9/11, Justice Department lawyers contended that a practice counted as “torture” only if it was “intended” to cause the kind of “severe pain” generally associated with “death, organ failure, or the permanent impairment of a significant body function.” Since waterboarding and other “enhanced” interrogation practices were intended to elicit information rather than to cause pain for the sake of pain — and since the pain caused by waterboarding wasn’t as bad as death or organ failure — it wasn’t torture. (Under this logic, even the use of thumbscrews presumably wouldn’t count as torture, as long as the interrogators’ goal was intelligence, not vengeance.)

Several senior military lawyers offered strenuous objections. For instance, Air Force Maj. Gen. Jack Rives argued that the “extreme interrogation techniques” approved by the Justice Department violated domestic criminal law and the Uniform Code of Military Justice. But military resistance was largely limited to memos. No one staged a coup; no senior officer resigned in public protest. At the end of the day, the military brass followed orders from their civilian masters.

If history and social psychology have taught us anything, it’s that most people, civilian and military alike, will go along with the instructions of those they perceive as authority figures, no matter what horrors they have to witness or carry out — and for the most part, that’s precisely what happened after 9/11. Although it was CIA rather than military personnel who were implicated in many of the most egregious post-9/11 abuses, military officers went along with plenty of bad actions and sometimes instigated them.

Even firmer resistance from military officials probably wouldn’t have stopped the Bush administration from resorting to torture. In the years immediately following 9/11, White House officials turned repeatedly to the CIA for those jobs that made military personnel squirm. And Congress didn’t exactly demand compliance with the spirit of the law, either. Though lawmakers eventually passed legislation prohibiting some of the most abusive interrogation practices, they also repeatedly altered U.S. laws in ways that enabled those same abuses to go unpunished. They provided a “just following orders” defense, for instance, and watered down previous war-crimes legislation, with retroactive application. If the Bush administration eventually abandoned its most controversial detention and interrogation practices, it wasn’t because the military rebelled — it had more to do with the fatigue engendered by years of bad publicity, ceaseless external legal challenges and pressure from unhappy U.S. allies.

We’ve seen similar dynamics in recent debates about controversial Obama administration practices. Several military leaders have questioned the legality, morality and strategic wisdom of secret U.S. drone strikes outside of traditional battlefields, particularly when the targets are U.S. citizens. But just as they did under President Obama’s predecessor, Justice Department lawyers have provided memos offering legal justifications , muting any military resistance. U.S. military intervention in Syria is also arguably illegal under international law, and numerous lawyers in the armed forces have expressed private concerns about this and about the legality of current U.S. action under the 2001 Authorization for Use of Military Force. But here again, don’t expect a mutiny or a coup.

However much we might sometimes wish it to, law doesn’t exist wholly beyond politics — and neither does the military. We shouldn’t expect troops to stand up against illegal or immoral practices when the White House, the CIA, Congress and most members of the American public can’t be bothered to do so.

So if you don’t want Trump — or any potential president, now or in the future — to bring back thumbscrews, carpet bombing and the deliberate targeting of innocent civilians, don’t count on the military to stop him. Our best hope, against this and all other forms of savagery and bigotry, is exactly what it’s always been: Citizens need to speak out strongly and repeatedly, in the media, in the classroom, in the neighborhood and on the streets.

And don’t forget to vote.

Twitter: @brooks_rosa

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