Donald Trump is setting himself apart by promising not just to fight terrorists but to torture them and kill their loved ones. (Jabin Botsford/The Washington Post)

Donald Trump went even further in his support of waterboarding and other barred interrogation techniques Wednesday, saying that as president he would use torture in the fight against terrorism.

“Don’t tell me it doesn’t work — torture works,” Trump said during a campaign event at a retirement community here Wednesday morning. “Half these guys [say]: ‘Torture doesn’t work.’ Believe me, it works.”

Most Republican candidates for president approve of the use of waterboarding in extreme cases, calling it a valuable enhanced interrogation technique that is not torture, which is forbidden under U.S. and international law.

But in an election year in which many conservative voters are deathly afraid of Islamic State terrorists, Trump is setting himself apart by promising not just to fight terrorists but also to torture them and kill their loved ones — and to treat all foreign Muslims as suspects by barring them from entry to the United States.

“They’re chopping off our heads in the Middle East,” Trump said Wednesday. “They want to kill us, they want to kill us. They want to kill our country. They want to knock out our cities.”

Donald Trump speaks with Bill Herbkersman in Bluffton, S.C. (Jabin Botsford/The Washington Post)

With his comments, Trump has reignited debate over extreme interrogation measures that the CIA embraced after the Sept. 11, 2001, attacks but discontinued more than a decade ago.

Waterboarding involves restraining prisoners on their backs with their feet higher than their heads, then covering their faces and pouring water into their mouths and noses, making them feel as though they are drowning.

Although the CIA held more than 100 prisoners in its secret overseas prisons, only three are known to have been subjected to waterboarding. Among them was Khalid Sheik Mohammed, the self-proclaimed mastermind of the 9/11 attacks, who was waterboarded 183 times before the agency abandoned the practice amid concerns that its legal footing was slipping.

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For months, Trump has repeatedly called for the use of waterboarding and other unidentified techniques that are even more severe. Up until Wednesday, Trump had stopped short of calling such techniques torture, although his comments seemed to show him openly embracing the idea of torturing people who are at odds with the United States. Trump’s campaign manager and spokeswoman did not respond to requests for comment Wednesday.

In late November, Trump said at a rally in Columbus, Ohio, that he would approve the use of waterboarding “in a heartbeat” because “only a stupid person would say it doesn’t work.”

“If it doesn’t work,” Trump said, “they deserve it anyway, for what they’re doing.”

Trump’s call for waterboarding and more extreme measures is always met with warm applause and cheers at his rallies — forcing his opponents into a tricky position. The traditional GOP response has been that torture is wrong but that waterboarding is not torture. How do they deal with a rival who embraces waterboarding as being torture and calls for its use?

Even the staunchest defenders of the CIA program have stopped far short of Trump’s position. In books and television appearances, CIA veterans have maintained that the agency’s methods were legally approved by the Justice Department and never constituted torture. But no prominent former CIA executive has argued that the program should be reinstated, and many believe that even if a future president were to order a resumption of waterboarding or other brutal measures, agency operatives would almost certainly refuse.

The CIA has maintained that it got valuable intelligence from the program, but it came at a considerable price. Agency operatives remained under a cloud of criminal and congressional investigations for years. A multi-year Senate probe completed in 2014 found that even CIA insiders were at times deeply disturbed by what they witnessed.

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CIA medical personnel warned that waterboarding sessions often described to policymakers as a carefully administered procedure had deteriorated to a “series of near drownings.” In 2002, agency employees at a secret prison in Thailand broke down emotionally after watching harrowing interrogations of al-Qaeda suspect Zayn al-Abidin Muhammed Hussein, better known as Abu Zubaida, “some to the point of tears and choking up.”

Obama banned CIA enhanced interrogations within days of taking office in 2009. Since then, terrorism suspects captured overseas have been questioned by a team including FBI and CIA representatives who are supposed to abide by strict U.S. military interrogation guidelines.

During the Feb. 6 Republican debate in New Hampshire, former Florida governor Jeb Bush — whose brother authorized waterboarding — said that it was “used sparingly” and that he would not take action to revive it. Sen. Ted Cruz (R-Tex.) said waterboarding “does not meet the generally recognized definition of torture” but that he “would not bring it back in any sort of widespread use.” Sen. Marco Rubio (R-Fla.) seemed to avoid answering the question by saying that U.S. officials “should not be discussing in a widespread way the exact tactics that we’re going to use because that allows terrorists to know to practice how to evade us.”

Meanwhile, at the same event, Trump pledged to “bring back a hell of a lot worse than waterboarding.”

The morning after the debate, ABC’s “This Week” host George Stephanopoulos asked Trump whether he “would authorize torture.” Trump responded: “I would absolutely authorize something beyond waterboarding.”

That Monday, the day before the New Hampshire primary, Sen. John McCain (R-Ariz.) — who was tortured as a prisoner during the Vietnam War — said that “waterboarding and other inhumane interrogation techniques” did not prevent further attacks on the country and “compromised our values, stained our national honor, and did little practical good.”

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On the same day, however, Trump mocked Cruz for not taking a stronger stance on waterboarding. As he spoke at a rally, a woman in the audience called Cruz “a pussy” — an insult that Trump repeated to the crowd.

Waterboarding came up again Wednesday when South Carolina state Rep. Bill Herbkersman (R) asked Trump a series of questions in a fireside-chat-style event that lasted 33 minutes.

“On that whole thing of politically correct, would you allow U.S. interrogators to waterboard terrorist prisoners in order to extract information?” Herbkersman asked.

“Absolutely,” Trump said to strong applause from the audience of about 500 retirees, who often laughed as Trump discussed the issue.

On Cruz, Trump said that “he didn’t want to get involved because he thought waterboarding was bad, so — of course it’s bad, but it’s not chopping off heads, folks. Okay? That I can tell you.”

Trump said that he would “immediately” resume waterboarding and other techniques that are “much worse” because the United States is facing a barbaric enemy. He called waterboarding a “minor form” of interrogation.

“Some people say it’s not actually torture — let’s assume it is,” Trump said. “But they asked me the question: ‘What are you going to do on waterboarding?’ Absolutely fine, but we should go much stronger than waterboarding. That’s the way I feel.”

Greg Miller in Washington contributed to this report.