The top American commander in Iraq is expected to tell Democrats in Congress part of what they want to hear next month when he briefs Washington on the status of the surge, namely that at some point American troop levels in Iraq will recede.

In September, when General David Petraeus will give classified and unclassified testimonies and recommendations to Congress, he will stress that unprecedented progress has been made against Al Qaeda and Iran’s network in Iraq, lessening the need for the current troop levels of approximately 160,000. At the same time, the general will warn that any military progress made against America’s foes will be lost if the surge ends precipitously.

Speaking to a small group of American reporters who accompanied him to the Amariyah neighborhood of Baghdad, General Petraeus said, “We know that the surge has to come to an end, there’s no question about that. I think everyone understands that by about a year or so from now we’ve got to be a good bit smaller than we are right now,” the Associated Press reported.

A military officer working closely on the Iraq strategy yesterday elaborated for The New York Sun. This officer stressed that in regions such as Anbar province, where more than 30,000 Marines have brought relative peace and destroyed most of Al Qaeda’s networks, there would likely be reductions in force.

“In areas where there has been local political progress, where indigenous security forces have been successful and where many insurgents have joined the American side, there will be draw-downs of combat soldiers,” this officer said.

A senior scholar at the Brookings Institution, Michael O’Hanlon, yesterday said there could be room for moderate force reductions this time next year.

“The number of troops is negotiable in Iraq, but the concept for the Bush administration is not negotiable,” he said. “And the concept of course is dense overall force concentrations and an effort to partner with Iraqi security forces to overcome sectarian tendencies. There are places where we can do more of the advisory role, but implementing this uniformly across the country is not a realistic option.”

The military now estimates some 25,000 former Sunni insurgents have put down their weapons and joined the fight against Al Qaeda, a figure General Petraeus is expected to offer Congress when he descends on Washington in September.

While Sunni insurgents in the past have switched sides and America has turned over neighborhoods and regions to an unprepared and infiltrated Iraqi army, the process for vetting the ex-terrorists is more complete now. For example, former members of groups like the Islamic Army of Iraq and the 1920 Brigade are biometrically tagged, making it possible for the American command in Iraq to know where they are at all times. In addition, an intricate process to collect accurate census information on these former insurgents, such as their extended family and place of residence, is completed before the old weapons are exchanged for American ones.

Finally, while reconciliation has stalled at the national level, the military will claim success in establishing local governance councils to oversee the details of reconstruction.

This strategy of paring down enemies to shrink the pool of terrorists attacking Iraqis and Americans was on display yesterday in Amariyah. General Petraeus visited the area to pay his respects to a former member of the Islamic Army of Iraq, whose nom de guerre is Abu Abed.

According to the Associated Press, General Petraeus asked Mr. Abed to give an interview to a Sunni Arab television station, in which he promptly guaranteed the safety of the neighborhood’s residents who had fled. According to the Associated Press, Mr. Abed joined the American side in reaction to the strict imposition of Islam from Al Qaeda in Iraq.

“You have to pinch yourself a little to make sure that is real because that is a very significant development in this kind of operation in counterinsurgency,” General Petraeus told the Associated Press. “It’s all about the local people. When all of a sudden the local people are on the side of the new Iraq instead of on the side of the insurgents or even Al Qaeda, that’s a very significant change.”

The emphasis on how success in turning the population against the enemy in Iraq is made possible in part by this year’s troop surge will likely be a key theme in trying to persuade centrist Democrats to hold off on voting to end the troop escalation this fall. In some ways, however, it will compensate for what is likely to be a disappointing assessment from Ambassador Ryan Crocker. Mr. Crocker is expected to lower expectations for any prospect of a political compact from the national government, a point driven home in the last two weeks as Prime Minister al-Maliki’s unity coalition becomes more tenuous with Sunni and Shiite Islamist defections.

General Petraeus has some important factors on his side. A Gallup poll earlier this month found that 47% of Americans hold a favorable impression of the general, while only 21% of Americans have an unfavorable view of him.

The general, who oversaw the drafting of the Army’s first counterinsurgency manual since the Vietnam War, will also be running his own press strategy in Washington as opposed to delegating this task to either the White House or the Pentagon.