In his most political speech since he left office in 2009, George W. Bush said voters should choose a candidate who is "measured and thoughtful" over the loudest and angriest man in the room.
"I understand that Americans are angry and frustrated but we do not need someone in the Oval Office who mirrors and inflames our anger and frustration," Bush said. "We need someone that can fix the problems that cause our anger and frustration, and that's Jeb Bush."
Bush called the 2016 campaign a "serious election for a serious job," in a 20-minute speech that was both sober and at times light-hearted.
"I'm proud of his candidacy," Bush said about his brother. "I came here for two reasons -- one, because I care deeply about Jeb, and two, because I care deeply about our country."
Trump, for his part, said again Monday that the American people were not safe under President George W. Bush.
"Excuse me, the World Trade Center came down during the reign of George Bush, right? I mean, it came down," Trump told reporters during a press conference in South Carolina. "We weren't safe. That was the greatest attack in the history of the United States." Trump also criticized Bush over the war in Iraq, which he said destabilized the Middle East.
George W. Bush did not take on those accusations head on, but he had a clear warning for his party about Trump. The former president pointed to the abundant "name-calling" in the 2016 election -- an apparent reference to the punches thrown between Jeb Bush and Trump in recent months -- and joked that according to their father, George H.W. Bush, "labels are for soup cans."
"(The) presidency is a serious job that requires sound judgment and good ideas," Bush said.
Although the former president did not once mention Trump's name in his remarks, the implicit message was clear: Trump is not a serious candidate.
"Strength is not empty rhetoric, it is not bluster," Bush said, but rather based on"integrity and character."
"In my experience, the strongest person usually isn't the loudest in the room," he added.
In a speech that was largely centered around national security and terrorism, Bush reflected on the attacks of September 11, 2001
-- and the "tough calls" he had to make in the days that followed — as he presented his brother as the most "measured and thoughtful" candidate in the GOP pack.
"When Americans woke up on September 11, we did not know that the world was forever changed that day," Bush said.
He urged voters here to "look for a candidate who has genuine respect for the United States military (and) who will support them on the battlefield and when they return home."
The long-running tensions between Jeb Bush and Trump boiled over on Saturday at the Republican debate in Greenville
, when Trump attacked George W. Bush's national security record. The New York real estate mogul called the former president's decision to go to war in Iraq a "big fat mistake."
Jeb Bush hit back with force.
"My dad is the greatest man alive, in my mind. While Donald Trump was building a reality TV show, my brother was building a security apparatus to keep us safe and I'm proud of what he did," he said.
Trump took things one step further, saying it was under George W. Bush's watch that the World Trade Centers in Manhattan fell on 9/11.
"That's not keeping us safe," the New Yorker said, as the audience booed loudly in disapproval.
Since leaving Washington in 2009 after eight years in the White House, Bush has not shown interest in being in the public spotlight or playing a leadership role within the Republican Party. His visit to North Charleston comes as other members of the Bush clan have also started to play a more active role in Jeb Bush's presidential campaign. In New Hampshire, Bush's mother and former first lady, Barbara Bush
, campaigned with her younger son.
On Monday, George W. Bush also discussed life after the White House, which he lightheartedly referred to as "the after life."
"Laura and I loved our years in Washington, but we really don't miss it too much," he said, bringing the audience to laughter.
He joked that the couple now spends a lot of time on their ranch in Texas, and that that as tree farmers, he still gets opportunities to practice his "stump speech."
He also quipped about his new hobby of painting: "Let me assure you, I know that the signature's worth more than the painting."
There were plenty of attendees at the North Charleston Coliseum who said their main motivation for coming to Jeb Bush's rally Monday night was to see an ex-president in person.
Sharon Hickey, a New Hampshire resident who rents a home in South Carolina for a part of the year, said it was "wonderful" to see George W. Bush campaign for his brother.
"We're honored to be here to see, to be in the presence of, a former President," Hickey said.
Joe Kelley, a retired fighter fighter from Boston who owns a second home in Murrells Inlet, is currently undecided but leaning towards Jeb Bush and Marco Rubio. As he waited to George W. Bush to take the stage, he said he thought the ex-President did a "fine enough job" in the White House.
"In my life time I've seen one President in person, Bill Clinton
," Kelley said. "Just to see a president in person -- I think it would be nice."