BAGHDAD - At an intersection in the Sadiyah section of the capital, near the tip of the thumb formed by a sharp bend in the Tigris River, stands a stark example of what underlies Iraq's sectarian war and why any peaceful outcome will not be determined by U.S. combat power.

On a recent afternoon, a convoy of Humvees brought Army Brig. Gen. John Campbell for a look. The deputy commanding general of the 1st Cavalry Division did not like what he saw.

To the east of a north-south boulevard the Americans have dubbed Route Spruce, Campbell surveyed the eerie emptiness of an enclave that until recently was populated mainly by Sunnis. It now resembles a ghost town.

"It looks devastated," he told an Associated Press reporter who accompanied him.

On display were rows of abandoned shops, empty homes, piles of debris. All were evidence of the retreat of hope for a reconciling anytime soon between two rival religious sects -- Shiites and Sunnis -- in a desperate battle for power.

Here, you can sense the quandary facing the Bush administration, bedeviled by an unpopular war with no end in sight after more than four years and at least 3,631 U.S. military deaths.

The Sunnis in Sadiyah have been driven away -- Campbell called it a "purge" -- by encroaching extremists of the Mahdi Army, the Shiite militia that Campbell says is using gangland-style tactics to gain ground. Sunni extremists affiliated with the al Qaeda terrorist group are beginning to slip into the same neighborhood.

The problems in Sadiyah show how complex this war is. They also show why many U.S. military officers in Iraq believe they must sustain the troop buildup -- despite strong opposition by many in Congress -- well beyond September. That is when an important review of the buildup's results is due.

And they expose the deep divisions in the Iraqi government, including a persistent fear among the majority Shiites that the Sunnis are determined to regain the dominant position they held under the late Iraqi leader Saddam Hussein.

On Saturday, a group of American officers led by the 1st Cavalry's other deputy commanding general, Brig. Gen. Vincent Brooks, met at an American base in the southern reaches of Sadiyah with Khalid H. Rasheed, an adviser to the Sunni deputy prime minister, Salam al-Zubaie. Brooks pressed the case for Iraqi government action in Sadiyah as well as in the even more troublesome area of Doura, just to the east.

Brooks and Col. Ricky Gibbs, commander of the 4th Brigade, 1st Infantry Division, which is in charge in Sadiyah and throughout a larger area of southern Baghdad known as Rashid, made the case to Khalid for the national government to hire more local Sunnis as police and to improve local public services.

"There's not enough Iraqi Army (troops) to go around," Gibbs told the AP, so the government needs to authorize more Sunni volunteers for the police force. Also, the government needs to put more money into rebuilding the area, starting with electricity, water and sewage services that have been devastated, he said.

The American military can help in the short term, but they cannot be expected to provide the ultimate answer. "It has to be an Iraqi solution," Gibbs said.

What Brooks and Gibbs heard from Khalid, a Sunni, was a familiar complaint, that the problem is with the Shiites.

"The root of the problem is related directly to the prime minister himself," Khalid said, referring to Nouri al-Maliki, a Shiite. "Sectarian-driven advisers" are steering the prime minister away from an accommodation with the Sunnis and delaying efforts to improve conditions in Sadiyah, Khalid said.

So when local Sunnis volunteer to join forces with the Americans against al Qaeda, al-Maliki's advisers tell him, "`OK, look, it's a plot to topple you or overthrow the government,'" Khalid said, speaking through an interpreter.

In a similar vein, the Sunni commander of Iraqi Army forces in the area, Brig. Gen. Feras Abdul Qader, told Campbell during his visit on Thursday that Shiites in Sadiyah are complicit in helping the Mahdi Army extremists to drive out the Sunnis, whose homes are then sold by the Mahdi Army to Shiite families.

Feras said the Shiite locals are either collaborating with the extremists or are cowering in fear.

"Either way, they are helping the insurgents -- either directly or indirectly," Feras said through an interpreter.

Adding to the mix is the presence in Sadiyah of an Iraqi national police unit, known as the "Wolf Brigade," that Campbell said has a well-earned reputation for human rights violations. He said he is leery of the brigade commander, Brig. Gen. Salaam Jewad Kadhim, a Shiite. At a meeting in Salaam's office, Campbell pointedly cautioned him against missteps that can ruin his credibility with the locals.

Accompanying Campbell to Sadiyah was the top Iraqi Army commander for Baghdad, Gen. Abud Qanbar. He said in an AP interview that the area's problems show why it is too early for U.S. troops to leave.

"We need a lot of work to build our forces and make them stronger than they are today," he said through an interpreter. "We need them (U.S. troops) to be around us" for many months to come.

Reminded of the pressure in Congress to pull out troops soon, Abud counseled patience.

"It needs a lot of study before that decision can be made," he said. "Maybe at the beginning of the year or the middle of next year" it will be time to begin pulling out, he said.