Promising to use torture on Isis detainees is a guaranteed applause line for GOP presidential candidates.

And that doesn’t surprise Harvard law professor Alberto Mora. But the former Pentagon lawyer is warning the rhetoric is damaging America’s reputation abroad and handing the enemy a valuable tool.

Alberto Mora has more reason than most to cheer Donald Trump’s call for reversing the ban on torture. After all, the former U.S. Navy general counsel was in the Pentagon on 911 when terrorists crashed a 757 into the building.

But when Mora heard detainees were being water boarded at the Marine base in Guantanamo, and that there were White House “torture memos” justifying it, he fought back from the inside.

In a guest lecture this week, Mora told Florida State University law students why he thinks President George W. Bush made a huge mistake.

“The net result of this is that the zone of individual protection from cruelty has shrunk, personal rights and liberty have been diminished and the United States has established the strongest and most formidable precedent for the proposition that immunity from accountability for torture is acceptable in democratic nations.”

Mora also has more reason than most to fear state-sanctioned abuse. He was 8 when his parents fled Castro’s Cuba for Jackson Mississippi. When he worked for the Department of Defense, the University of Miami law school grad served as the U.S. Navy’s chief ethics officer.

U.S. torture of detainees at Guantanamo, Cuba and Abu Ghraib, Iraq, helped terrorist leaders recruit thousands of fighters, Mora says .

“The U.S. Joint Chiefs of Staff in 2005 determined that the number one and number two identifiable causes of U.S. combat deaths in Iraq in 2005 were No. 1, Abu Ghraib and No. 2, Guantanamo.”

U.S. diplomats lost the moral high ground they used so effectively to shape foreign policy since the end of the Second World War, Mora argues. And as a result, he says, the U.S. has also lost leverage to protect its own citizens and soldiers from abuse.

“The United States might be more restrained in our use of cruelty than other states. But if Syria, North Korea or Cuba decided to be completely unconstrained, than who could object? The answer is of course no one.”

That’s why, Mora says, there’s more urgency than ever to shut down Guantanamo.

“Guantanamo is a crime scene where the crime of torture was committed with impunity. For many around the world, the term Guantanamo has not unfairly come to symbolize and be synonymous with the term American injustice. Every person here should regard that as intolerable.”

Attempts by foreign torture victims to sue in US courts have been dismissed on national secrecy grounds, Mora says. One torture victim who was kidnapped by the CIA by mistake was compensated by a Canadian court, Mora says.

One FSU law student wanted to know about the fallout for the legal profession.

“Has there been any type of professional discipline? And if so, how do you think that that could influence other aspects of accountability?

Hardly, Mora says. John Yoo, a former White House counsel and author of the torture memos is a professor at Berkley. Yoos’ former boss is a federal appeals judge.

But those who participated at the highest levels are scorned by their colleagues, Mora says. And that counts for something.

“These memoranda that permitted these policies were gross violations of legal professionalism and gross violations of ethical requirements for individual attorneys. That judgement is not insignificant. “

Mora says he’s encouraged that Harvard students are demanding changes in the law school curriculum to make future lawyers aware of the pitfalls.

Mora says any president considering the use of torture would do well to remember the words of the French philosopher Albert Camus.

“In fighting a war, we must take care not to use those weapons that would destroy what we seek to protect. And my message today is torture is exactly that kind of weapon.”

Mora’s speech marked the 25th anniversary of the Journal of Transnational Law & Policy.