"That was the result, not of military actions, certainly, alone. It was the result of, really, a political shift where the population led by the sheiks of major tribes decided to reject al Qaeda and its Taliban-like ideology, and the extremist behavior that they have come to associate with it," Petraeus said.
"That is what brought the level of violence down so dramatically. Because al Qaeda no longer finds a hospitable place in the Euphrates River Valley the way it did, certainly, in the past."
Petraeus began his role as the commander of the mutlinational forces in Iraq in February, and said the U.S. forces would not have had this success without Iraq's help.
"We've been banging away at al Qaeda for years … but until we could hold them with the help of the local population and local volunteers, those operations were never as … meaningful as they have been in recent months. And that's what we are trying to do in other locations in Iraq," he explained.
That has also led to a rise in the detainee population over the past six months, as more al Qaeda operatives have been caught, Petraeus said. And while there is always the concern that they will gain strength, the "pool of potential recruits has shrunk.
"Their sanctuaries have shrunk considerably … so, they don't have the ease of movement, the ease of locations, where they're safe the way they were before," he said.
He specifically points to progress with respect to Syria. "We believe that there have been fewer suicide bombers coming through Syria, and we are cautious about this assessment, but we do think that the Syrians may have been taking more active steps against al Qaeda, which is understandable," Petraeus said. "I mean, if al Qaeda were ever to succeed in Iraq, the next thing they'd do is turn … [to] Damascus. I can assure you."
While Petraeus called this "long-term" work, he was quick to point out that he does not necessarily mean the U.S. troop levels must remain at their current size.
"It's a crucial recognition, and we have to acknowledge that — however, you don't have to stay at the level of forces during that time, and I think the question in everyone's mind, frankly, is 'OK, so, there does need to be a long-term strategy. What's the level of our commitment during that time?' And the answer is, certainly, a good bit less than what we have committed right now," Petraeus said.
As he prepares to address Congress, Petraeus is aware some lawmakers may have already formed an opinion about how to proceed with what has become an unpopular war.
"Our job is to provide the information. And that's all we can do … and then, it's up to them, obviously," he said. "And there may be some who have literally already made up their minds."
While he's aware of how prominent he has become in the debate, Petraeus is trying to stay out of the politics and just present what he observes in Iraq.
"We're not taking messages from people about what our message is. Our message is what is happening … we are happy to report successes, but we are obligated to report setbacks — and we will … that's our duty, and, you know, we are in charge of America's most precious resource — that's its sons and daughters."
As for the duration, U.S. troops will remain in Iraq. The top commander said he sees this as a "traditional counterinsurgency," which would typically last a decade.
"I think that would be the case here. The question, though, is at what level of involvement by the U.S. and coalition forces," he said.
"Iraq will be dealing with a variety of issues for quite some time, without question. What everyone needs to figure out is how much will we need to contribute, and I think the answer is, less."