Gen. Ray Odierno, the U.S. Army’s top officer, pushed back on the Iraq War blame game that has dominated the GOP 2016 presidential campaign trail, saying that the U.S. military’s withdrawal from Iraq in 2011 was the Bush administration’s plan all along. Odierno, formerly the senior U.S. general in Iraq, said he was unconvinced at the time that the Iraqi parliament would have approved a longer stay for American troops had Obama administration officials successfully negotiated for it.

The Iraq War has jumped back into headlines recently as Republican candidates attempt to tie the U.S. withdrawal in 2011 — and former Secretary of State Hillary Clinton’s role in it — to the rise of the Islamic State. In a major national security speech on Tuesday, Jeb Bush criticized Clinton and President Barack Obama for removing U.S. troops from Iraq. “That premature withdrawal was the fatal error, creating the void that ISIS moved in to fill – and that Iran has exploited to the full as well,” said Bush, a former Florida governor and brother of President George W. Bush.

Odierno, who is to retire Friday, spent much of his final press conference at the Pentagon reflecting on what might have prevented the Iraqi government from falling apart after American troops left. They departed in December 2011, after which the Iraqi Security Forces “became significantly politicized,” he said.

“I remind everybody, us leaving at the end of 2011 was negotiated in 2008 by the Bush administration. That was always the plan. We had promised them that we would respect their sovereignty,” said Odierno, who commanded troops in Iraq for more than five years between 2003 and 2010, including two years as the top American general in the country.

Keeping U.S. troops in Iraq beyond 2011 would have required the Iraqi parliament’s approval, which was hardly guaranteed.

“I don't know if we could have convinced them to do that or not,” Odierno said. “I will say we had the same problem initially, when we initially hammered out the [status of forces] agreement in ’08 as well.” Without that agreement, U.S. troops ran the risk of being arrested for any misconduct.

Odierno said he was not part of the Obama administration's negotiations to extend the U.S. military’s stay. But considerable reporting has documented the administration’s efforts at the time to craft an Iraqi government it felt was needed to justify keeping U.S. troops there after the Bush agreement expired in December 2011. Critics, including Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., have said for years they believe Obama’s team did not really try to persuade Baghdad to accept an extension, and instead allowed the Bush-negotiated agreement to expire so that Obama could fulfill his campaign promise to end the Iraq War.

“I think the military operations we conducted provided an opportunity for us to be successful,” Odierno said, a refrain he has diplomatically repeated since his dramatic departure from Baghdad.

Asked if the 2003 U.S.-led invasion of Iraq was a mistake, Odierno said, “All I know is that Saddam Hussein was an incredibly ruthless person who was suppressing his population.”

“I talked to all the Iraqi generals,” he said. “They’ll tell you there were nuclear weapons. They believed there were. The bottom line is they absolutely believe there were nuclear weapons on the ground. To say we shouldn’t have went in there now because we know there wasn’t any or we didn’t find any, I think is a little bit of hindsight.

“We don’t know where we would be right now if Saddam Hussein was still in power,” Odierno continued. “He was moving toward terrorism and I believe if he continued to have problems, we don’t know what he might have done in terms of being part of the problem with terrorism.”

Looking forward, Odierno expressed further support for embedding American soldiers with Iraqi Security Forces fighting ISIS militants.

“I believe that if we find in the next several months we’re not making the progress ... we should probably absolutely consider embedding some soldiers with them, see if that would make a difference,” Odierno said. “That doesn’t mean they would be fighting, but it maybe embedding them and moving with them. I think that’s an option we should present to the president when the time is right.”

Standing before a podium raised to accommodate his 6-foot, 6-inch frame, the general said the solution to sectarian rivalry in the wartorn nation might be an Iraq that “might not look like it did in the past.”

But it’s up to the Arab states and diplomats, not the military, to figure that out, Odierno said. “I absolutely believe that the region has to solve this problem,” he said. “The U.S. cannot solve this problem for the region. They have got to get involved and we got to be part of the solution.”

When U.S soldiers were in Iraq during the last decade, it “allowed us to be honest brokers” between different sects, Odierno said. “I think maybe as we all look back, leaving some soldiers on the ground might have helped a little bit and maybe prevented where we are now,” he said.

Before any lines are redrawn on the map, Iraq must deal with ISIS first.

“I think ISIL has been vaunted somewhat,” Odierno said when asked if the militant group is winning. “They have not made any progress since we started airstrikes. I think we have gained back some territory, mostly by the great work of the Kurds and some work by the Iraqi Security Forces.”

American combat forces could probably defeat ISIS, Odierno said, but within months after leaving, separatists would likely rise again without political and economic improvements.

“For me it’s about changing the dynamics, the political dynamics, the economic dynamics and it has to be done by those in the region,” Odierno said. “I think it’s important for us to support that. It’s important for us to support that by training and trying to develop capability and capacity.”

In May, Odierno said that embedding U.S. troops, who have been training and advising the Iraqis since last year, “probably would make this more effective,” but could possibly could deepen sectarian or ISIS violence.

ISIS still retains between 20,000 and 30,000 soldiers despite a year of American-led airstrikes which U.S. officials say have killed thousands of militants and extremist leaders.

“They're not as capable as they were a year ago, they're not as capable as they were 18 months ago,” he said. “But they are still able to recruit, and get people to come in and fight — and that's what's concerning to me. This is why this is not a solely military solution.”