Tough talk about torture is a guaranteed applause line for Donald Trump on the GOP presidential stump.

Trump has repeatedly advocated waterboarding, an enhanced interrogation technique that simulates the feeling of drowning.

“In the Middle East, we have people chopping the heads off Christians. … I would bring back waterboarding and I’d bring back a hell of a lot worse than waterboarding,” he said to applause in a recent debate, without ever specifying what “a lot worse” would entail.

“I don’t think we go far enough,” he said, drawing loud clapping at a rally last week in Las Vegas.

“We don’t go far enough,” he repeated, prompting now-thundering applause and chants of “USA! USA!”

Trouble is, waterboarding and “a lot worse” interrogation techniques are illegal.

To bring it back, Trump would have to get Congress to repeal the law that prohibits it. That could be an uphill battle. Last June, Republicans joined all 44 Senate Democrats in voting 78-21 to reaffirm a ban on harsh interrogation techniques.

That vote came just months after a Senate intelligence committee report denounced brutal interrogation methods as ineffective.

“In general, what I’ve taken away from our practices and what the research shows is that the rapport-based techniques — that we operate under and focus on — are shown to elicit greater detail in a quicker fashion,” said Frazier Thompson, director of the High-Value Detainee Interrogation Group, a secretive team of interrogators from the FBI, Defense Department, the CIA and other intelligence agencies that interrogates top suspects believed linked to plots against the U.S. or its allies.

“Every individual is different and every situation is different,” Thompson said, adding that it’s important to know where the suspect is emotionally and intellectually so that an interrogator with the right skill set can build rapport and elicit intelligence.

Trump, however, told voters in Bluffton, South Carolina, simply that, “torture works.”

The Army Field Manual specifically bans the military from using so-called enhanced interrogation techniques, including waterboarding. However the CIA used waterboarding after the attacks of Sept. 11, 2001, and other methods that are illegal under domestic or international law. Those included some physical contact such as slapping and slamming an inmate and psychological torture. One inmate at a secret CIA “black site” died of exposure, according to the Senate panel’s report.

In 2009, Obama issued an executive order saying all U.S. government personnel and contractors — not just those in the military — are prohibited from using any interrogation techniques that aren’t in the Army Field Manual.

Last year, Democratic Sen. Dianne Feinstein of California and Republican Sen. John McCain of Arizona introduced an amendment to the 2016 defense policy bill that essentially put the executive order into law. Feinstein said it was important because a future president could lift Obama’s executive order.

This year, after hearing Trump and other GOP presidential candidates talk favorably about torture, McCain weighed in. McCain was shot down over North Vietnam in 1967, held as a prisoner of war in Hanoi and tortured before his captors released him six years later.

“Given the loose talk on the campaign trail about reviving waterboarding and other inhumane interrogation techniques, it is important to remember the facts,” McCain said.

“These forms of torture not only failed their purpose to secure actionable intelligence to prevent further attacks on the U.S. and our allies, but compromised our values, stained our national honor and did little practical good,” he added.

Some of McCain’s Republican colleagues and some former CIA officials, however, maintain that waterboarding and other harsh methods have yielded vital intelligence.

In his book, “The Great War of Our Time,” former deputy CIA director Mike Morell argued that the techniques used on al-Qaida detainees by the CIA produced crucially important intelligence. “I believe that waterboarding was one of the two most effective of the all the harsh techniques (the other being sleep deprivation),” he wrote.

Americans remain split on the issue.

In a poll conducted 10 years after the 2001 attacks, 52 percent of Americans favored harsh interrogation techniques against individuals suspected of terrorism. Fifty-two percent said torture can sometimes or often be justified while 46 percent thought torture was never or rarely justified.

The 2011 poll of 1,087 adults by The Associated Press and the NORC Center for Public Affairs Research at the University of Chicago had a margin of error of plus or minus 4.1 percentage points.

(AP)