GOP presidential candidate Jeb Bush alluded to his brother's "Mission Accomplished" boast during an event in Ankeny, Iowa, Thursday.

Story highlights

Jeb Bush, at forums in Iowa, talked about his brother and the Iraq war

Bush also criticized President Obama for pulling troops out of Iraq

Would he repeal Obama's torture ban? Bush declined to say

Davenport, Iowa CNN  — 

Jeb Bush, who’s tried relentlessly this year to be his “own man,” is once again back in the spotlight doing the delicate dance of defending George W. Bush yet still distancing himself enough from his brother so as to quash concerns of Bush-wary voters.

At an event in Davenport, Iowa, on Thursday, the Republican presidential candidate spoke extensively about the 43rd president and the war in Iraq, as the former Florida governor is aggressively trying to blame the growth of ISIS on his brother’s successor, President Obama.

Blasting Obama for prematurely withdrawing troops during his first term and allowing ISIS to “fill the void,” Bush argued the President isn’t taking the terror group seriously enough and simply wants to “run out the clock” on his final two years as president.

“In my mind, this is all an exercise to just get to January of 2017 and head off to Chicago,” Bush said at the event, a forum hosted by the Americans for Peace, Prosperity, and Security.

Bringing up the war

But when asked if ISIS would be a problem today if the United States hadn’t invade Iraq in the first place, Bush didn’t have as firm of an answer.

“That is such a complicated hypothetical,” he said. “I’ll tell you, though, taking out Saddam Hussein turned out to be a good deal.”

“If you think about all the variables that could’ve happened had we not invaded then, we might have invaded later, who knows? I mean that’s – then you’re in back to the future and you might as well make a movie out of it,” he later added.

It was just a few months ago when Bush faced a different hypothetical: Would you have invaded Iraq knowing what we know now about the faulty intelligence? It took Bush several days to say he would not have invaded, but the week-long struggle became easy fodder for both Democrats and his Republican rivals.

And some Republicans were again surprised to see Bush revive discussion of the Iraq war this week when he delivered a foreign policy speech at the Ronald Reagan Presidential Library in which he laid out his own strategy to take out ISIS but focused heavily on the troop withdrawal from Iraq.

GOP presidential rival Chris Christie said bringing up the war is “absolutely not” the right way to help Republicans. Meanwhile, Democrats were quick to point out that Bush made little mention of his brother’s role in starting the security agreement that ultimately led to the withdrawal. Hillary Clinton’s presidential campaign, for example, accused Bush of trying to “rewrite history and reassign responsibility.”

Ambiguity on torture ban

But in the forum Thursday, led by intelligence reporter Ken Dilanian with the Associated Press, Bush tried to keep the focus on the successful 2007 surge – saying the “mission was accomplished” – and criticizing the ensuing withdrawal of troops a few years later, rather than dwell on who started the war.

Bush did say he disagreed with one decision from his brother’s administration.

“The decision to dismantle the Iraqi army was a mistake, and I think my brother would admit that today,” he said.

And he felt it was right for the former president to largely do away with the CIA’s use of enhanced interrogation methods. President Obama later issued an executive order that legally banned those techniques.

But for his part, Bush declined to say whether he would leave that ban in place or repeal it. “I don’t want to make a definitive, blanket kind of statement,” he said, saying he prefers to be “cautious” in making such predictions. “When you are president your words matter.”

Later at a separate event in Ankeny, Iowa, he was asked by reporters to clarify whether he was leaving open the idea of allowing methods like waterboarding again in the future.

“I’m not ruling anything in or out,” he said, but stressed “we don’t do torture.”

Mission accomplished or impossible?

Bush also vigorously defended his brother in the forum for keeping the U.S. homeland secure in the days after 9/11.

“I’m not saying this because I’m a Bush,” he said. “I’m proud of what he did to create a secure environment for our country.”

Also later Thursday, reporters asked Bush if he intentionally invoked the phrase “mission was accomplished” as a nod to his brother, who famously spoke in 2003 in front of a banner with almost the same wording splashed across it, yet the war continued on for years.

Jeb Bush, somewhat annoyed, argued reporters were overanalyzing his remarks.

“I know you’re obsessed with all this and that’s your job, but it was a mission that was accomplished,” he said, referring to the 2007 surge. “(The phrase) is used. It was actually a movie. It’s been a sequel. Tom Cruise has made a really good living out of it,” he went on to say, appearing to conflate the term with the movie series “Mission Impossible.”

“There’s nothing subliminal about it or psychological” he said. “The surge worked and it’s been recognized as having worked, and Iraq was left fragile but secure. And a lot of people sacrificed a lot. A lot of vets now are proud of that effort. They may be disabled. People lost their lives in that effort and we should reflect on it and appreciate the courage it took to do a really heroic task.”

CNN’s Dana Bash and Janet DiGiacomo contributed to this report.