Former Florida governor Jeb Bush (R) took heat for a series of answers he gave on whether he would have authorized the war in Iraq. (Jhaan Elker/The Washington Post)

This story has been updated.

TEMPE, Ariz. – After a week of painfully struggling to talk about the war in Iraq started by his brother, Republican presidential hopeful Jeb Bush stated definitively here Thursday that he would not have invaded that country based on the intelligence failures that now are known.

“Knowing what we now know, what would you have done? I would have not engaged. I would not have gone into Iraq,” Bush said at a campaign stop before a few dozen local business leaders at Four Peaks Brewery in Tempe.

Bush tried to explain his days of difficulty articulating a clear position on Iraq as the result of being reluctant to say anything that might suggest he was ungrateful for the sacrifice of the U.S. armed forces and their families during 12 years of war.

"It’s very hard for me to say that their lives were lost in vain," Bush said. "In fact, they weren’t. We have the greatest military in the face of the earth.” He added, "Their sacrifice was worth honoring, not depreciating."

Later, answering questions from reporters, Bush said he had not spoken to his brother, George W. Bush, about Iraq in recent days.

"I don't go out of my way to disagree with my brother," Bush told reporters. "I am loyal to him. I don't think it's necessary to go through every place that I disagree with him."

Bush contended that in 2008, when his brother was preparing to turn over the White House to Barack Obama, Iraq was stable. "It was fragile, but it was stable," he said, although he added, "Relitigating this and going through hypotheticals does no good for" the families of those soldiers who died.

[On Iraq, Jeb Bush stumbles and the GOP hopefuls pounce]

All week, Bush, a former Florida governor who is considered a leading 2016 presidential hopeful, has struggled to answer questions about the Iraq war and show how he would be a different president than George W. Bush.

His troubles began in an interview with Fox News anchor Megyn Kelly, which aired Monday, in which he suggested he still would have authorized the war in Iraq despite knowing of the intelligence failures.

Bush's answer, coupled with his inconclusive and wavering comments about Iraq on Tuesday and Wednesday, drew criticism from many of his likely GOP opponents, most of whom have proclaimed they would not have authorized the Iraq invasion knowing what we now know.

Bush said here in Tempe that he wants his 2016 campaign to focus on the future, not on his brother — nor their father, George H.W. Bush, also a former president.

"What’s the role of America going forward?" he said. "Are we going to pull back now and be defeatist and pessimistic or are we going to engage in a way that creates a more peaceful and secure world? That is what 2016 is about – not about 2000, not about 1992, not about 1980," a reference to the years when his brother and father ran for president.