At a rally in Charleston, S.C., former president George W. Bush campaigned for his younger brother, Jeb, and cracked a few jokes as the Republican candidate looks toward the South Carolina primary. (Victoria Walker/The Washington Post)

Former president George W. Bush made a folksy and resolute return to the political arena here Monday night after a seven-year hibernation, trying to enliven his brother’s flagging campaign and stop Republicans from coalescing around front-runner Donald Trump.

Though he never uttered the billionaire mogul’s name, Bush delivered an unmistakable rebuke to Trump’s candidacy ahead of next Saturday’s critical South Carolina primary by touting the importance of humility in leadership and warning that “bluster” and “theatrics” must not be mistaken for strength.

“Americans are angry and frustrated, but we do not need someone in the Oval Office who mirrors and inflames our frustration,” Bush said. He added, “Strength is not empty rhetoric. It is not bluster. It is not theatrics. Real strength, strength of purpose, comes from integrity and character.”

In another implicit contrast with Trump, Bush said that his brother was “a man of deep and humble faith that reveals itself through good works, not loud words.” He then said, “All of the sloganeering and all of the talk doesn’t matter if we don’t win.”

Bush has deliberately avoided politics since leaving the White House in 2009, but made an exception to help revive his brother’s once-promising candidacy. Bush’s friends said that the 43rd president — like his father, George H.W. Bush, the 41st president — has been bewildered by Trump’s rise and durability.

Former president George W. Bush waves to a crowd of supporters as he takes the stage with his wife, Laura, and brother, Jeb, on Monday in North Charleston, S.C. (Alex Holt for The Washington Post)

Jeb Bush, who has struggled in a season dominated by outsider candidates, is hoping for a revival in South Carolina after poor finishes in the Iowa caucuses and New Hampshire primary. The joint appearance by the Bush brothers drew more than 1,000 to a convention hall in North Charleston, making it easily the most energetic and well-attended event since Bush’s campaign launch last June in Miami.

But at a time when voters are rejecting the governing establishment, the rally carried risks for Jeb. It serves as a visceral reminder of his family’s dynasty as well as invites a new assessment of George W. Bush’s legacy, including the unpopular war in Iraq, which Jeb has uncomfortably struggled to deal with.

Since last Saturday’s debate in Greenville, Trump, who said he first opposed the Iraq invasion in 2003, has kept up a drumbeat against George W. Bush’s foreign policy, trying to guarantee that Jeb Bush does not reap the rewards of his brother’s support without getting mired in a public discussion of Iraq.

Trump staged a news conference four hours before the Bush event and just four miles away, where he told reporters that George W. Bush was partly to blame for the terrorist attacks on Sept. 11, 2001.

“Excuse me,” Trump said. “The World Trade Center came down during the reign of George Bush, right? It came down. . . . We weren’t safe.”

Former president George W. Bush smiles as his brother, Jeb, recalls a story about their childhood on Monday in North Charleston, S.C. (Alex Holt for The Washington Post)

Trump said the war in Iraq led to instability in the Middle East that gave rise to Islamic State terrorists. “Saddam Hussein was a bad guy,” he said. “One thing about him: he killed terrorists. Now Iraq is [a] harbor for terrorism.”

Bush spoke movingly Monday night about the moment he learned about the Sept. 11 attacks. And Jeb Bush came to his brother’s defense, saying that listening to Trump’s Sept. 11-related attacks made him wonder, “If I closed my eyes, I thought it was Michael Moore on the stage,” referring to the liberal documentary filmmaker.

Also defending Bush was his vice president, Richard B. Cheney, who said Monday night on Fox News Channel that Trump was “way off base” and was uninformed.

“I was in the White House bunker all day helping coordinate, manage our response to 9/11,” he said. “I didn’t see Donald Trump there. I’ve never seen him involved in any way that would lead me to believe that he had any firsthand or practical experience about it.”

If the day projected a united front against Trump, it also felt like a flashback. Bush’s hair was grayer and thinner, but he sounded the same: self-deprecating, and with a Texas twang.

He said that he and his wife, Laura, who looked on smiling, were enjoying their presidential “afterlife” and spending time at their Texas ranch.

“We’ve become tree farmers. It gives me some time to practice my stump speech,” Bush said playfully. “I’ve been one to defy expectations. I’ve been mis-underestimated most of my life.”

Bush earlier Monday met privately in Columbia with Gov. Nikki Haley (R) and her family, and he heaped praise on her in his remarks here. “Thank goodness our country welcomed her parents from India when they immigrated here in 1969,” said Bush, in an allusion to the anti-immigrant talk that has come from Trump and others.

Polls suggest that George W. Bush is popular among Republicans in South Carolina, but his legacy is more complicated. He remains a polarizing figure, certainly with Democratic and independent voters, but also among some grass-roots activists on the right who think he was not sufficiently conservative on fiscal matters.

The general public turned sharply against the Iraq war and Republican strategists think relitigating the war is hardly helpful to Jeb Bush or to the party.

Former South Carolina governor David Beasley (R) said Trump was smart to raise doubts about the Iraq war because it “created confusion in the minds of a pro-George Bush voter.”

“They’ll still like George, but they may think, ‘Maybe we did make a mistake,’” Beasley said. “They’ll think, ‘I love George, but I just don’t know if I can trust my vote with another Bush at this time.’ ”

Many of the people who packed the convention hall here to see George W. Bush had warm feelings about his presidency. Bonnie Welch, 70, a retired teacher from Myrtle Beach, said Trump’s attacks were unfair.

“President Bush was so taken back by what happened” on Sept. 11, 2001, she said. “As I was sitting and watching that on TV, the look on his face said it all.”

Bush appeared to relish being in the political spotlight again — especially in South Carolina, the state where he notched a pivotal victory in 2000.

He sprinkled his 20-minute address with homespun tales. He recalled walking in the Okra Strut in Irmo, a festival celebrating a local crop. He talked about the time he had breakfast at Tommy’s Country Ham House in Greenville and an animal rights activist drove into the parking lot and dumped manure to try to block his exit.

“It was kind of a sign of things to come,” Bush quipped, before adding that at Tommy’s, “even a steaming pile of manure can’t ruin their good bacon.”