Through a one-way mirror, journalists observe a focus group of Donald Trump supporters in Alexandria, Va., on Wednesday. The group was organized by political consultant and pollster Frank Luntz. (J. Lawler Duggan/for The Washington Post)

It was the most brutal attack ad run against Donald Trump, and it was tanking. Twenty-nine voters, all of whom supported or used to support Trump, watched retired Air Force Col. Tom Moe not so subtly compare the Republican front-runner to Adolf Hitler.

“You might not care if Donald Trump says he’s going to round up all the Hispanic immigrants, because you’re not one,” Moe said onscreen. “You might not care if Donald Trump wants to suppress journalists, because you’re not one. But think about this: If he keeps going, and he actually becomes president, he might just get around to you.”

Frank Luntz, the Republican media consultant who had put together this focus group, watched the dials turn down. On a scale of zero to 100, the ad’s effectiveness never got above 20. It did not help that the ad was produced for Gov. John Kasich (R-Ohio), a presidential candidate no one in the group supported.

“It was too far over the top,” one voter said.

“They use every trick in the book to make him look like the ultimate bad guy,” said another.

“It tried to make Trump look like the new Mussolini,” said one more disgusted voter. “I mean, that ain’t gonna happen.”

The presidential campaign for Gov. John Kasich (R-Ohio) put out a new ad, lashing out directly at fellow Republican candidate Donald Trump with a harsher tone than any other candidate has taken thus far. (John Kasich)

Next up was a lengthy compilation of Trump’s attacks on his fellow Republicans, over a pumping, distracting drumbeat. “He sweats more than any young person I’ve ever seen,” Trump said of Sen. Marco Rubio (R-Fla.). Carly Fiorina talked like a “robot.” Ben Carson was “pathological.” Jeb Bush had “no money” and was “meeting with Mommy and Daddy” for support.

The dials turned higher — because the audience was laughing along with Trump.

Tiffany Alm, 43, who moved to the Washington area from Wisconsin, responds to a question. (J. Lawler Duggan/for The Washington Post)

“It was like his greatest hits,” said Tiffany Alm, 43, a stay-at-home mom who had moved to the D.C. area from Wisconsin. “It’s Donald Trump, and it’s entertaining.”

Over three hours Wednesday in Alexandria, Luntz lobbed dozens of Trump-seeking missiles. All 29 in the group had voted for Mitt Romney in 2012. All either supported Trump or had supported him earlier in the year. To Luntz’s amazement, hearing negative information about the candidate made the voters, only a few of whom gave their full names to the press, hug the candidate tighter.

“Normally, if I did this for a campaign, I’d have destroyed the candidate by this point,” Luntz told a group of reporters when the session ended. “After three hours of showing that stuff?”

With only two exceptions, the three hours of messaging, venting and friendly arguments revealed the roots of Trump’s support. Participants derided the mainstream media, accusing reporters of covering snippets of Trump quotes when the full context would have validated him. They cited news sources they trusted — Breitbart News was one example — to refute what they were being told.

“You know what Trump does?” said Teresa Collier, a 65-year-old retiree. “He says something completely crazy, and I’m like, ‘Oh, my God!’ Then he dials back and starts explaining it and saying how he’d do it, and it makes sense.”

Only eight members of the group disagreed with Trump’s proposal for a temporary ban on Muslims entering the United States. One of the holdouts said he was hosting an exchange student from Saudi Arabia and did business in that country but could disagree with Trump about Muslims and vote for him anyway.

This voter listened as supporters of the plan explained that the media had lied about it, an argument furthered this week on conservative talk radio. As the night went on, the holdout said he had become more likely to back Trump.

Members of the focus group respond to questions. (J. Lawler Duggan/for The Washington Post)

None in the group wanted to find themselves on the side of the mainstream media — or of President Obama. When Luntz asked participants to sum him up in a word or phrase, “socialist” and “Jimmy Carter” tumbled forth until one man raised the ante.

“I wouldn’t urinate on him if he was on fire,” he said.

“That’s the meanest thing I’ve ever heard,” Luntz said.

Frank Lanzillo, a 59-year-old retired Marine, took that as a cue to explain just how anti-American the president really is.

“When you bend down to the Saudis, take your shoes off, put your hand on a Koran and then the Bible when you’re sworn in?” Lanzillo said. “He took his flag pin off. I’m a Marine and former deputy sheriff. He took that off, he was in the toilet to me. I would not only not piss on him if he was on fire — I’d throw gas on him.”

(The president briefly chose not to wear a flag pin during the 2008 campaign; he was not sworn in on a Koran.)

Asked whether the president was a Christian, only three of the 29 participants raised their hands. Asked whether he was born in the United States, eight said no. When Luntz returned to policy, mistrust of the president informed the exclamations of trust in Trump.

“Donald Trump says that President Obama wants to allow 250,000 Syrian refugees to come into the country,” Luntz said. “Who thinks that is mostly true?”

Nearly every hand shot up.

“Do you know that Obama has said he wants only 10,000 refugees?” Luntz asked.

“What’s in his heart?” asked one participant.

“He’d let as many in as possible,” insisted another.

“It happens again and again,” said Jeff Scrima, 38, who moved to the D.C. area after serving as mayor of Waukesha, Wis. “The State Department says one thing, Obama says something else, and they change the policy to match him.”

To Scrima and almost everyone else in the room, most criticisms of Trump broke down when they stopped to consider the source. Trump had warned that political correctness was killing Americans. The shooting in San Bernardino, Calif., had proved him right. One member of the group recalled angrily how the Texas administrators who had suspended a Muslim boy for bringing a strange-looking clock to school were demonized for simply being diligent. Tiffany Alm shared what her family had heard on vacation in Paris, right after the terrorism of Nov. 13.

“The news over there, the newspapers, they were interviewing Muslims,” Alm said. “And they were saying they don’t like America, they don’t like France, but they’re there. They say they won’t become terrorists, but they hate America and France and Western culture.”

Heads were nodding around the room. “I’ve read the Koran,” said Jeff Kelly, 57. “It says what it’s purported to say. I know it says you come across a non-Muslim, you kill him or convert him.”

Luntz moved on to questions about Trump’s claim that “thousands of Muslims” had “cheered the collapse of the World Trade Center.” Almost no one doubted Trump; more than a few people wondered why this was controversial. The youngest member of the group wondered why he never saw Muslims in the streets protesting terrorism. Kelly said that there was fresh audio evidence of Muslims celebrating the San Bernardino shooting, though he could not immediately recall the source.

All that really mattered was that the Republican establishment had failed, badly, and that Trump was offering a way out. Asked whom they would back in a three-way election with Rubio, Hillary Clinton and an independent Trump on the ballot, just 10 said they would support the Republican nominee. When Sen. Ted Cruz (R-Tex.) was swapped into the question, a bare majority — 15 — said they would stick with the party.

“The Republican establishment just had a heart attack,” Luntz said.

Political consultant and pollster Frank Luntz poses questions to the group. (J. Lawler Duggan/for The Washington Post)

Nothing seemed to budge the Trump voters. Almost all of them agreed that Clinton had committed crimes. Almost all agreed that the last Republican president had been wrong to invade Iraq in 2003. Finally, Luntz asked for a thought experiment — to imagine incontrovertible proof that Clinton would win if Trump split the vote. Only then did the group agree to vote Republican over Trump.

“In that scenario, sure,” said a middle-aged participant named Michael. “But that won’t happen. Trump would win.”

That confidence only grew as Trump’s alleged gaffes and mistakes were laid out. At 6:30 p.m., when the session began, all 29 participants were asked to rate their likelihood of voting for Trump, and just 10 people said they were at nine or 10. After one hour of mostly negative questions about Trump, six more people joined that confident group.

“I’ve been talking about negatives, and you’re up on him!” said an astounded Luntz. “That’s the story of Trump’s poll numbers.”

Almost nothing was changing that picture. The group heard Trump insist that the wives of the Sept. 11, 2001, hijackers had been warned in advance and sent home. They saw Trump mock a New York Times reporter with a disability who had written about reports of post-Sept. 11 celebrations. Some people winced; more of them rationalized what Trump had been saying. “The real issue is that the reporter retracted his story after 14 years,” Scrima said.

(The reporter, Serge Kovaleski, then with The Washington Post, never retracted his article describing reports of a tailgate-style party of Muslims after 9/11. The article never described thousands of Muslims celebrating, and when interviewed about the article this year Kovaleski said he did not recall any reports describing numbers of that magnitude.)

In three hours, the only issue that moved voters against Trump was one that evoked memories of the 2012 election. The group was shown an ad in which contractors blamed Trump for the loss of their jobs.

That, one man said, made Trump look less electable. He was downgrading the likelihood of his own Trump vote — from nine out of 10 to just eight.

“I can’t wait for Iowa, because I now think Ted Cruz will win Iowa,” Luntz said. “That will be a rallying cry. Losing there might actually help Trump win New Hampshire.”

Correction: An earlier version of this article misspelled Serge Kovaleski’s name.