Republican presidential candidate Jeb Bush. (AP Photo/Kevork Djansezian)

This story has been updated

DAVENPORT, Iowa -- Jeb Bush vigorously defended some of the defining foreign policies and national security strategies implemented by his brother George W. Bush as president on Thursday, casting in a positive light elements of the Iraq War, a conflict that haunted much of his tenure.

He notably used wording similar to the "Mission Accomplished" banner that hung behind the 43rd president as he gave a speech on an aircraft carrier in 2003. The speech was one of the biggest embarrassments of his administration, since the war went on for years after that.

"I've been critical and I think people have every right to be critical of decisions that were made," Bush said Thursday. "In 2009, Iraq was fragile but secure. It was mission was accomplished in the way that there was security there and it was because of the heroic efforts of the men and women in the Untied States military that it was so."

In a question and answer session hosted by Americans for Peace, Prosperity and Security held on a college campus here, the Republican presidential hopeful said the removal of Saddam Hussein from power "turned out to be a pretty good deal," and he praised the 2007 troop surge his brother pushed as "an extraordinarily effective" strategy.

[Jeb Bush faults Hillary Clinton for ‘premature’ Iraq withdrawal]

On the debate over interrogation techniques, another issue that dogged his brother, Bush would not say for certain whether he would preserve the executive order President Obama signed banning enhanced interrogation. "I do think in general that torture is not appropriate," he said.

“I'm cautious about making commitments without having all the facts," he said. Bush defended the Guantanamo Bay detention facility, which Obama has struggled to try to close throughout his presidency. "This is not a torture chamber," he said, adding that he had seen it firsthand.

Bush went further than just lauding the the policy merits of the Iraq troop surge. He also commended his brother for not caving to the intense political opposition he faced at the time. "He had the courage to do something that is completely against the political grain," he said.

While Bush has sought some distance from his brother's controversial tenure and his famous last name -- "In Florida, they called me Jeb," he said at the first GOP debate -- the remarks highlighted how, at least on foreign policy, Bush does not intend to open up a deep divide with 43rd president.

On Iraq, Bush continued his assault on the policies of Obama and Democratic presidential front-runner Hillary Rodham Clinton, which he sharpened in major foreign policy speech Tuesday at the Ronald Reagan Presidential Library.  He blamed them for the problems that have arisen in the aftermath of the Iraq war.

Of Clinton, the former secretary of state, he said Thursday: "She traveled to Iraq once. Once during her time."

He argued that the negligence in the Middle East by Obama and Clinton helped give rise to the Islamic State terrorist organization, which has taken a foothold in Iraq and Syria.

"This is all an exercise to get past January of 2017 and head off to Chicago," he said of Obama.

Bush struggled to find the right wording at times. More than once, he referred to the "Wikipedia leaks," a reference to WikiLeaks, an origination that has published sensitive national security and diplomatic information.

Bush’s latest comments on Iraq came several months after he stumbled over several days to articulate how he would have handled the situation there.

“Knowing what we now know, what would you have done? I would have not engaged. I would not have gone into Iraq,” Bush said in mid-May during a campaign stop in Arizona.

Those definitive comments capped a painful twist in his presidential ambitions, as he struggled in a Fox television interview and in other campaign appearances to articulate what he would have done.

His answers ranged from “I would’ve” to “I don't know” to “Rewriting history is hypothetical.”

After clearly saying he would not have authorized the war, Bush admitted that the issue is fraught with personal pain for him: “I don’t go out of my way to disagree with my brother,” he said.

Polling continues to show that a majority of Americans in both parties believe the Iraq war was a mistake. George W. Bush’s popularity has rebounded, but he is still held responsible for the war’s poor execution.

Bush is headed west to campaign in the Des Moines area over the next two days. He will appear at at a classic car showroom Thursday evening, where he will help a local Republican Party fundraiser. On Friday, Bush will be at the Iowa State Fair, where he will speak from the Des Moines Register’s Soapboax, a must-stop for White House hopefuls.

A CNN/ORC International poll showed Bush winning the support of just 5 percent of likely Republican caucusgoers in Iowa, well behind front-runner Donald Trump, who was at 22 percent. Even apparent long-shots like Carly Fiorina and Mike Huckabee polled ahead of Bush.

In an effort to show strength ahead of his trip, Bush’s campaign on Thursday morning released a list of dozens of county leaders who have signed on with his Iowa campaign.

Bush joked about the challenge he faces in Iowa earlier this week at the end of his speech at the Reagan Library. Responding to a standing ovation from the crowd, he asked: "Can you all move to Iowa?"

But the first leg of his Iowa trip was defined heavily by his thoughts about his brother's eight years in the White House.

“I'm proud of what he did to create a secure environment for our country," Bush said.

Ed O'Keefe contributed to this post