BAGHDAD, Iraq – One year after a bombing demolished the gold-domed Shiite Muslim shrine in Samarra, plumes of thick black smoke hung over the Baghdad skyline Monday – the aftermath of the latest car bombing at the capital’s largest market.

Dozens were killed in the latest chapter of sectarian violence, which in the past year seems to have escalated out of control.

Since the Feb. 22 bombing in Samarra – a year ago Monday, according to the Islamic lunar calendar – Shiite attacks against Sunni mosques have become routine, as have Sunni attacks against Shiite mosques. Abductions are almost beyond count, and dozens of corpses turn up across the capital every day.

Fear of the other sect has stopped Iraqis from traveling to large areas of their country, and many have been forced out of their homes. Neighborhoods have been cleansed either by force or voluntary flight as battles between Shiites and Sunnis exploded.

The United Nations estimates that about half a million Iraqis have been internally displaced since the Samarra bombing, and the number is growing by 40,000 to 50,000 a month.

“The Samarra bombing just refers to a year of killing and abductions,” said Iqbal Ahmed, a Sunni who lives in the restive Dora neighborhood in south Baghdad. “The shrine can be rebuilt again, but you can’t get back the people you’ve lost. If the situation continues, we shall witness many Samarras to come.”

In the past year, Shiite cleric Muqtada al-Sadr’s Mahdi Army has pushed into Sunni neighborhoods on the west of the Tigris River, driving Sunnis from their homes with death threats and attacks. Meanwhile, Sunni forces, a combination of neighborhood youths, former members of Saddam Hussein’s Baath Party and Islamist groups, are pushing to maintain their hold on Sunni neighborhoods west of the river and defend their sect in the east.

Every home is forcefully asked to help. In Sadr-controlled neighborhoods, militiamen ask for donations and young volunteers. It’s a rare occasion when a man says “no” to Sadr’s Mahdi Army.

In Sunni neighborhoods as well, the call to arms comes with a knock at the door. The men of the house are asked to brandish their weapons and fight. No one is certain whom they’re supposed to fight, but anyone who doesn’t comply is apt to be called a traitor and no longer allowed to live at home.

Fate

With sectarian separation well under way, an individual’s fate can be determined by his or her tribal origin. Most Iraqis carry two identification cards – one with a Sunni tribal name for Sunni areas, another for Shiite neighborhoods for insurgent or militia checkpoints. The wrong name is a death sentence in Iraq.

Iraqis do not choose a side. Their sect does the choosing. The moment of decision is signaled by a firm knock at the door.

Ayad Sabti, a 43-year-old Shiite, lives in the neighborhood of Washash, near the once upscale shopping district of Mansour. He no longer does business in the Shorja market, which was bombed Monday, because his clients were Sunni and most of them have fled. Instead, he sometimes risks his life as a taxi driver, picking up strangers.

The last time he visited a Sunni town, north of Baghdad, he was detained by Sunni insurgents and managed to escape only by pretending he was a Sunni. He masked his Shiite accent and said he was from the Sunni town of Abu Ghraib, west of Baghdad, and that he was from the well-known Sunni tribe of Zobaa.

“I wish I could say the insurgents failed, but I have to admit that they succeeded and the best evidence is the sectarian violence,” Sabti said.