For the details of what's been done in and to Baghdad on our watch - including details of the purpose and effect of the "surge" (starting before Congress rubber-stamped it last year and ending by last fall) - read this excellent article by Michael Schwartz, author of an upcoming book about Iraq:

After a spring and summer of heavy fighting, however, the Americans were hardly close to pacifying the city. In a way, the surge had worsened the situation. Before it began, in many neighborhoods neither Sunni nor Shia militias were dominant; by the middle of 2007, virtually every community had its own mini-government, usually dominated by a militia that was hostile both to the occupation and the central government. To assert centralized authority over the city, each neighborhood would have had to be invaded again.

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Without announcing a change in policy, the Americans functionally abandoned the surge in the late summer 2007 in favor of a "live and let live" program of cooptation. On the Sunni side of the street, the Americans adopted a version of the Sunni "Awakening" movement that had arisen without American encouragement in Anbar Province the previous year, negotiating armed truces with their insurgent adversaries on a community-by-community basis. The Americans conceded to the militias the right to police their own communities, discontinued American offensives aimed at dislodging them, and halted the hated home invasions aimed at arresting or killing suspected insurgents. In exchange, the insurgents were to rein in attacks on American troops and suppress jihadist activity in their neighborhoods, thus curtailing the planning and execution of car bomb and other terrorist attacks on nearby Shia communities.

On the Shia side, the Americans essentially negotiated a ceasefire with the Mahdi Army, announced publicly as a unilateral stand-down by its leader Moqtada Al Sadr. The Sadrists curtailed the planting of lethal roadside bombs against the Americans and no longer sought to ambush American and Iraqi army troops moving through their neighborhoods. The Americans curtailed their raids and offensives in Sadrist neighborhoods and spent far less effort hunting down and arresting Sadrist leaders, except when they specifically broke the ceasefire.

[snip]

Their national spokesmen continued to insist that the country could not begin genuine reconstruction until the Americans left, and that the barriers they had played such a role in erecting -- sectarian as well as cement -- were removed.

Though many Baghdad communities are now experiencing their lowest levels of violence in two years, their situations are neither viable, nor stable. The cement barriers, which help to reduce violence, also make social and economic life nearly impossible. Most Baghdadis are now locked into their individual ghettos, terrified of strangers, often afraid to send their children to schools across barriers and neighborhoods, and unable to reach previously held jobs. Employers, deprived of needed workers and customers, have shuttered their establishments. The economy has largely ground to a halt.

For most of Baghdad, the Iraqi government is simply irrelevant. It has no administrative apparatus in any of these communities or the capacity to restore needed services. Its only visible presence, the Iraqi army, is commanded or controlled by American officers; insofar as Iraqi soldiers do act independently, they follow the leadership of Shia militia commanders, not the central government. In neighborhoods even a few hundred feet from the Green Zone, the Iraqi government does not exist.

[snip]

As early as May of 2006, Nir Rosen, one of the most informed and insightful journalists writing about Iraq, presciently described the American military's unenviable position in this way: "[T]he American Army is lost in Iraq, as it has been since it arrived. Striking at Sunnis, striking at Shias, striking at mostly innocent people. Unable to distinguish between anybody, certainly unable to wield any power, except on the immediate street corner where it's located… [T]he Americans are just one more militia lost in the anarchy." This description was never truer than today in Baghdad.

http://tomdispatch.com/post/174909/michael_schwartz_how_to_disintegrate_a_city

I wonder if any Members of Congress ever even bother to read such accounts, never mind ever making the effort to formulate questions based on such reports to hold to account the American implementers of such barbaric, futile tactics.

Here's more from the Iraqi perspective:

http://alternet.org/waroniraq/80469/?page=entire

Remember that for those Americans running the show in Iraq, staying is success - their (unspoken) agenda is profit, not peace, and oil deals unfavorable to the future of Iraq require our armed presence, the state and well-being of Iraq and Iraqis be damned.