BAGHDAD, Iraq — In the chaotic, hopeful April of 2003, Baghdad's Karrada district was one of those neighborhoods where residents showered flowers on U.S. forces entering the capital. Revelers threw water on one another and the Americans, exuding joy at the crushing of a dictatorship that had silenced, tortured and killed their people.

Now, with the end of the third and in many ways hardest summer of the U.S.-led occupation, the lights of Karrada are dimmer. The collapse of Iraq's central power system has left Baghdad averaging less than eight hours of electricity a day.

The crowds on the sidewalks have thinned — kidnapping and other forms of lawlessness since the invasion mean Baghdad's comparatively liberated women seldom leave home without a good reason.

Car bombings and other insurgent attacks, as unknown in Baghdad before the invasion as suicide subway bombings were in London until this summer, have killed more than 3,000 people in the capital since late spring.

Leaving the house for work each day has become a matter of turning the key and consigning one's fate to God, said Jassim Mohammed, 41, a Karrada merchant who has lost two of his friends and one of his lighting shops in car bombings since the Americans came.

"Now in Iraq, no one and nothing can protect you but that. Every morning you kiss them goodbye," Mohammed said, referring to his wife and children, "because you don't know if you will be back or not. Everyone in Iraq does that now."

Mohammed's remaining shop, its chandeliers sparkling with their Czech-made crystal pendants, is one of the last bright spots at night on Karrada's grubby streets.

Like the rest of Baghdad, Karrada is messier, more beat up than it was before the invasion. Merchants leave some damage from bombings unrepaired, anticipating more violence. Rubbish tends to pile up in once-tidy streets, neglected by a weak, cobbled-together government.

And more than two years after flowers and water cascaded onto the arriving Americans, what's being thrown on Karrada's streets, and who is throwing it, has changed as well.

Mohammed, a courtly, gentle-mannered man, carefully chose the harshest word he could think of for urine.

In Karrada this summer, Mohammed and the neighborhood watched as American soldiers on patrol grew irritated at an Iraqi who had left his car in the street to run inside a store on an errand, blocking their armored convoy.

The Americans took one of the empty plastic water bottles they use to relieve themselves when on patrol, Mohammed said. When the Iraqi driver ran out to move his car, an annoyed American plunked him with the newly filled bottle and rolled on, Mohammed said.

"He started crying," Mohammed said of the Iraqi driver, humiliated in front of the neighborhood.

Mohammed, who said he had been one of the happiest people in Karrada to see the Americans when they came in April 2003, retrieved the bottle and handed it to the weeping man.

"I said, 'Give this to the Iraqi government,' " Mohammed said. "Tell them this is the sovereignty the Americans have brought us."

Breakdown in order

Many in Baghdad were sure that the mightiest army in the world had a plan for what would follow the invasion. Hiding in their homes, they waited to be told what it was.

A month after the Americans arrived, Kareema, a 42-year-old engineering student, wondered when they would reschedule oral defenses for master's theses.

Kareema was sheltered in her dark home with her four sisters and sisters-in-law — all doctors or engineers who had devoted their lives to learning and their careers and waited only to resume them. Outside, looters had stripped classrooms of desks and blackboards, burned university buildings and ransacked a museum holding artifacts charting 5,000 years of civilization in Iraq.

The breakdown in order and the dismissal of Iraq's security forces unleashed a crime wave that lingers. Daylight kidnappings and robberies are common. Parents hire armed guards for their children's school buses. Boys and girls in middle-class neighborhoods routinely fight off strangers who attempt to shove them into the trunks or back seats of cars and take them away for ransom.

And three summers into the U.S. occupation, Kareema and her sisters and sisters-in-law cloak themselves in black and wear black gloves when they go out, a neighbor who knows them said. But these days, the neighbor said, the sisters seldom go out.

When the Americans came, they protected only a few public buildings from looters, said Nagham Emad, 23, a university student lingering in a Karrada ice-cream shop, spooning up her sundae slowly to put off the return to a dark, hot home.

One of the buildings was the Oil Ministry, Emad said. The others were Saddam Hussein's marble-and-gilt palaces, which the Americans took over for their offices. Now, when power outages darken the rest of Baghdad, she said, massive generators make the barricaded, highly guarded palaces of the Americans glow.

Electricity a problem

The lack of electricity, like the lack of security, remains one of the two biggest complaints among Baghdad's 6 million people.

The Americans had underestimated the problems with Iraq's infrastructure, a U.S. official in Baghdad said on condition of anonymity. A U.S. military spokesman, Lt. Col. Steve Boylan, said a large part of Baghdad's electricity problem is that even as supply increases, it is being inexorably outstripped by demand.

But the problems go beyond the dilapidation of the electrical grid under Saddam, the unplanned-for insurgent sabotage that regularly undoes repairs, and myriad other difficulties.

Rather than being centrally controlled, the flow of power throughout Iraq is allocated by switches at hundreds of substations across the country, the U.S. official said. Without a strong central government to enforce compliance, substations at times balk at sharing electricity, and the Shiite Muslim south and Kurdish north cut the flow to Baghdad.

As a result, the official said, not only are Baghdad's homes and businesses robbed of power, but the city's leaky water system continually runs dry and its purification plants face contamination.

A similar web of problems has plagued Iraq's oil industry. Insurgent attacks, artificially low prices and unchecked smuggling have helped cripple American plans to make Iraq self-sufficient through its oil industry. Iraq exported 1.46 million barrels a day in August, down from July, and down from the 2 million barrels a day before the U.S.-led invasion.

Insurgent attacks at the end of August shut down the main pipeline from the northern oil fields just as it was being brought back on line after attacks blocked exports for most of 2004. The shutdown came as Hurricane Katrina hit the U.S. Gulf Coast and world oil prices jumped to more than $70 a barrel.

Iraq, holder of the world's second-largest oil reserves, earlier this month instituted gas rationing, allowing each vehicle in Baghdad onto the streets only every other day. Heads of households struggled to get themselves to work and their children safely to school.

By the end of that week, rationing briefly overtook security and electricity as Baghdad residents' main topic of complaint in a summer that was too hot, too dark and too dangerous.

Safety, normalcy sought

Across Iraq, many people express shared sentiments about the past. They are happy that Saddam and his repressive regime are gone, but they are nostalgic for the safety, the lights and the other elements of normal life of that time.

Their thoughts about the future vary widely. Saif Ali is a 27-year-old merchant with a mobile phone shop two doors down from Mohammed's lighting store. Like many Shiites now assured of power by their majority status under Iraq's version of democracy, he is hopeful.

But their thoughts about the present are uniform.

"We can't think about how bad it is," Ali said.