Boos followed Donald Trump's comments mentioning the September 11th attacks. | AP Photo Trump crosses the 9/11 line ‘If it doesn't backfire, then it will be official; nothing can stop him,’ GOP strategist says.

GREENVILLE, S.C. — Jeb Bush’s campaign thinks George W. Bush is its not-so-secret weapon in next Saturday’s pivotal primary. Donald Trump couldn’t care less.

Holding a 20-point lead in the state over his nearest rival with a week to go, Trump blasted the former president for the national security record his brother’s campaign plans to tout, blaming him during a GOP debate Saturday night not just for the Iraq War but also for the 9/11 terrorist attacks.


“The World Trade Center came down during your brother’s reign. Remember that," Trump said to the former Florida governor, prompting a long, contentious back-and-forth.

In a state that’s home to a large number of military installations and veterans, the supercharged showdown between two candidates who’ve been sparring for months could play big, potentially reordering the race in the final week.

Our Principles PAC, launched last month with the purpose of attacking Trump, is preparing to blanket South Carolina's airwaves with a new ad featuring Trump's past statement that impeaching George W. Bush "would have been a good thing."

“I think most South Carolinians understand what President Bush did to protect our country and know that 9/11 was no fault of his, and they appreciate what he did over those eight years to respond and keep us safe,” said Glenn McCall, one of South Carolina’s RNC committeeman, in the spin room after the two-hour debate here.

That’s what Bush’s team is hoping for. Public and private polls show Bush running in a distant fourth place in South Carolina, a state where another lackluster showing could be crippling for his campaign. Following the debate, Sen. Lindsey Graham, Bush’s top surrogate in the state, was effusive in praising his debate performance.

“He had the guts to stand up to a bully,” Graham said. “This is clearly getting under Donald Trump’s skin. I hope the people of South Carolina will send a message to Donald Trump that we don’t like Putin, we like W.”

Bush's campaign has long grappled with how and where to deploy the former president, whose controversial record makes him a liability in some states and, should Jeb Bush get that far, the general election. But military-heavy South Carolina, where the former president is set to make his first public appearance on his brother’s behalf on Monday, has long been eyed as a state where George W. Bush would be an asset, especially in a competitive primary like the one that's now playing out.

The rally in North Charleston on Monday that will feature both Bush brothers marks the former president's first public campaign appearance and is suddenly a centerpiece of the campaign’s effort to frame the choice for South Carolina voters as a matter of which candidate will make the best commander in chief.

Trump, intentionally or not, may have just played into his rival's strategy.

“Everything we know about political strategy suggests that Trump's decision to attack George W. Bush will backfire,” said Curt Anderson, the GOP strategist who guided Bobby Jindal’s campaign last year. “If it doesn't backfire, then it will be official; nothing can stop him.”

Trump has proven to be remarkably bulletproof over the first seven months of his campaign, maintaining his position atop the polls despite — perhaps, because of — his penchant for stirring seemingly never-ending controversies. His campaign manager, Corey Lewandowski, shrugged off questions following Saturday night’s debate about whether the tough attack on George W. Bush would backfire.

“We’ve never followed polls, I think you guys know,” Lewandowski said. “This is a different campaign. We talk about the things people want to talk about; we talk about the things people talk about at their dinner table. It’s very clear that Mr. Trump’s positions don’t change based on what polling numbers say or what the public perception is. He talks from the heart, and he talks about it just like you would with your family.”

In fact, Trump has blamed George W. Bush for 9/11 many times before, just never on a debate stage before a television audience of millions. It started when moderator John Dickerson asked him about a past statement in which he suggested that the 43rd president should have been impeached for lying about Iraq’s alleged weapons of mass destruction in order to justify going to war.

“Obviously, the war in Iraq was a big fat mistake,” said Trump, who mocked Jeb Bush for taking five days to answer a question last May about whether, with the benefit of hindsight, he’d have made the decision to go to war in Iraq.

Then, Trump took his criticism even further, saying the former president did not keep America safe. And moments later, after Marco Rubio defended George W. Bush's record by saying the blame for the attacks fell on Bill Clinton, Trump doubled down.

"The World Trade Center came down during the reign of George Bush. He kept us safe? That is not safe. That is not safe, Marco. That is not safe," he continued. "The World Trade Center came down because Bill Clinton [didn't] kill Osama bin Laden when he had the chance to kill him. And George Bush — by the way, George Bush had the chance, also, and he didn't listen to the advice of his CIA."

“How did he keep us safe when the World Trade Center … excuse me,” he said as the crowd booed. “I lost hundreds of friends!” Trump shouted.

Jeb Bush, who has been victimized by Trump’s badgering insults for months, shot back that he was “sick and tired of [Trump] going after my family.”

“While Donald Trump was building a reality TV show, my brother was building a security apparatus to keep us safe,” he said. “I’m proud of what he did.”

Trump interrupted with the 9/11-related attack, and the room booed.

Asked whether he still supports impeachment, Trump didn’t directly answer, instead railing against the “lies” that, in his view, led up to the war in Iraq.

“You call it whatever you want,” Trump said. “They lied.”

Alex Isenstadt contributed to this report.