Washington - The war in Iraq has now lasted longer than the U.S. involvement in the war that President Bush's father fought in, World War II.

As of Sunday, the conflict in Iraq has raged for three years and just over eight months.

Only the Vietnam War (eight years, five months), the Revolutionary War (six years, nine months), and the Civil War (four years), have engaged America longer.

Fighting in Afghanistan, which may or may not be a full-fledged war depending on who is keeping track, has gone on for five years, one month. It continues as the ousted Taliban resurges and the central government is challenged.

Bush says he still is undecided whether to start bringing U.S. troops home from Iraq or add to the 140,000 there now.

He is awaiting the conclusions of several top-to-bottom studies, including a military review by Gen. Peter Pace, chairman of the Joint Chiefs of Staff.

Expected soon, too, are recommendations from an outside blue-ribbon commission headed by former Secretary of State James Baker, a Republican close to the Bush family, and former Rep. Lee Hamilton, an Indiana Democrat who was one of the leaders of the Sept. 11 commission.

The Iraq war began on March 19, 2003, with the U.S. bombing of Baghdad. On May 1, 2003, Bush famously declared major combat operations over, the pronouncement coming in a speech aboard an aircraft carrier emblazoned with a "Mission Accomplished" banner.

Yet the fighting has dragged on, and most of the 2,800-plus U.S. military deaths have occurred after Bush suggested an end to what he called the Iraq front in the global fight against terrorism.

Politicians in both parties blame the increasingly unpopular war for GOP losses on Capitol Hill in the November elections that handed control of the House and Senate to Democrats.

Twice before in the last half-century have presidents - Harry S. Truman in Korea and Lyndon B. Johnson in Vietnam - been crippled politically by prolonged and unpopular wars.

Bush last week visited Vietnam for the first time, attending a summit of Asian and Pacific Rim nations. Asked if the Vietnam war held any messages for U.S. policy in Iraq, Bush said it showed that "we'll succeed unless we quit."

John Mueller, an Ohio State University political scientist who wrote the book "War, Presidents and Public Opinion," said Americans soured on Iraq after "doing a rough cost-benefit analysis. They say, 'What's it worth to us and how much is it costing us?'"

By that standard, Americans were willing to abandon the Iraq war long before they turned against the war in Vietnam, Mueller suggested. "So that, for example, when more than 2,000 Americans had died in Iraq, support lowered. It took 20,000 deaths in Vietnam to lower support for that war to the same level," he said.

In the casualty count, the Civil War was the most lethal, with military deaths of the North and South combined totaling at least 620,000. By comparison, the total for World War II was roughly 406,000; Vietnam, 58,000; Korea, 37,000; World War I, 116,000.

The outgoing Republican chairman of the Senate Armed Services Committee, Sen. John Warner of Virginia, a veteran of World War II and a former Navy secretary, noted solemnly at a recent hearing of his committee that Sunday would mark the day when U.S. was involved longer in the Iraq war than it had been in World War II.

Yet the October 2002 congressional resolution that authorized the Iraq war "addressed the Iraq of Saddam Hussein, which is now gone, and no more a threat to us," Warner said.

While the United States is helping the Iraq's current government to assume the full reins of sovereignty, "we need to revise (our) strategy to achieve that goal," Warner said.

U.S. involvement in the Iraq war has outlasted that of the Korean War (three years, one month); the War of 1812 (two years, six months); the U.S.-Mexican War (one year, 10 months); World War I (one year, seven months); the Spanish American War (eight months); and the first Persian Gulf War (one and a half months).

Democrats and Republicans are divided about what to do next in Iraq.

Many Democrats and some Republicans have called for a phased withdrawal. Some lawmakers, including Sen. John McCain, R-Ariz., a 2008 presidential hopeful, are urging that more U.S. troops be sent to help stabilize Iraq.

Sen. Carl Levin, the Michigan Democrat who will be the next chairman of the Senate Armed Services Committee, argues for beginning to bring troops home soon. "We should put the responsibility for Iraq's future squarely where it belongs, on the Iraqis," Levin said. "We cannot save the Iraqis from themselves."

Experts of various political stripes have suggested that the options are few.

"No mix of options for U.S. action can provide a convincing plan for 'victory' in Iraq," said Anthony Cordesman, an Iraq analyst at the Center for Strategic and International Studies. "The initiative has passed into Iraqi hands."

Baghdad, Iraq - Iraq's Shiite prime minister, struggling to prevent sectarian violence from sending Iraq into full-fledged civil war, is facing strong criticism from top Shiite and Sunni Arab leaders alike as he prepares for a summit with President Bush next week.

On Saturday, a prominent Sunni religious leader warned that Iraq's escalating sectarian violence will spread throughout the Middle East unless the international community withdraws support for Prime Minister Nouri al-Maliki's government.

"I call on the Arab states, the Arab League and the United Nations to stop this government and withdraw its support from it. Otherwise, the disaster will occur and the turmoil will happen in Iraq and other countries," said Sheik Harith al-Dhari, who heads the Association of Muslim Scholars.

Last week, Iraq's Interior Ministry issued an arrest warrant against al-Dhari, saying he was wanted for inciting violence and terrorism.

On the other side of Iraq's sectarian divide, Shiite politicians loyal to the radical anti-American Shiite cleric Muqtada al-Sadr have threatened to boycott parliament and the Cabinet if al-Maliki goes ahead with the planned summit in Jordan on Wednesday and Thursday. The political bloc, known as Sadrists, is a mainstay of support for al-Maliki.

The White House has said the meeting is still on.

Iran, the top U.S. rival in the region, had planned its own summit Saturday, inviting the presidents of Iraq and Syria in what was seen as a bid to assert its role as a powerbroker in Iraq. Syria did not respond, perhaps to avoid annoying the U.S., and Iraq's president said he could not get to Iran before Sunday at the earliest because Baghdad's airport was closed to commercial flights following a deadly attack Thursday in Sadr City.

Suspected Sunni insurgents killed 215 people in the Shiite slum with mortars and five car bombs in the deadliest single attack of the war. On Saturday, Sadrist lawmaker Qusai Abdul-Wahab blamed U.S. forces for the attack, saying they failed to provide security.

As Vice President Dick Cheney traveled to the neighboring Sunni country of Saudi Arabia on Saturday to seek help in calming Iraq, Iraq's sectarian violence shifted to Diyala province north of Baghdad, where gunmen broke into two Shiite homes and killed 21 men in front of their relatives, police said. U.S. and Iraqi forces also killed 58 insurgents during fighting in the same region.

In central Iraq, a suicide car bomber attacked a checkpoint near Fallujah, killing three Iraqi civilians and a U.S. service member, and wounding nine civilians and an American service member, the coalition said. The dead included two Iraqi children and an adult.

A U.S. Marine also died from wounds sustained while fighting in Anbar province on Friday, the military said, raising to at least 2,874 the number of U.S. servicemen who have died since the war began in 2003. So far, 54 American service members have died this month in Iraq.

Six people were killed in other violence in Iraq on Saturday, and 19 bodies were found, police said.

Iraq's government has been unable to prevent revenge attacks by Shiite militias and Sunni Arab insurgents, despite the 24-hour curfew it imposed Thursday night on Baghdad's 6 million residents. After only scattered violence occurred in Baghdad on Saturday, the government announced it would allow residents to leave their homes Sunday but keep the ban on all vehicles for another day.

In Diyala province, a hotbed of Iraq's Sunni-Arab insurgency, gunmen raided the two Shiite homes late Friday, police said. The attack targeted members of the al-Sawed Shiite tribe in the village of Balad Ruz, 45 miles northeast of Baghdad, according to a police officer who spoke on condition of anonymity to protect his own security, as officials often do in the volatile province.

The gunmen broke into the both houses as their large extended families slept, marched everyone outside, lined up the 21 men and shot them to death as the women and children watched, police said.

Police could not reach the remote village to collect the bodies and take them to a morgue until Saturday, police said, adding that they do not known whether the attack was motivated by sectarian hatred or a tribal dispute.

In other parts of Diyala, a largely rural area of farms and orchards, police killed 36 insurgents and wounded dozens of others in clashes Saturday, police said. U.S. and Iraqi forces also conducted several raids north of Baghdad, killing 22 insurgents and a civilian, and destroying a factory used to make roadside bombs, the military said.

Baghdad was quieter than it had been on Friday, when rampaging militiamen burned and blew up four mosques and torched several homes in the mostly Shiite neighborhood of Hurriyah, witnesses and police said. Iraqi soldiers at a nearby army post failed to intervene in the assault by suspected members of the Shiite Mahdi Army militia or subsequent attacks that killed as many as 25 Sunnis, said police Capt. Jamil Hussein.

The U.S. military said Saturday that Iraqi soldiers securing Hurriyah found only one burned mosque and were unable to confirm residents' and police accounts that six Sunni Arabs were dragged from Friday prayers and burned to death.

On Friday, al-Sadr, the anti-American Shiite cleric, urged al-Dhari, the Sunni leader, to issue a religious edict condemning Sunni attacks on Shiites.

In an apparent response, Al-Dhari said during his news conference in Cairo, Egypt, that his Association of Muslim Scholars has repeatedly condemned the killing of Iraqi Muslims and attacks on their homes and mosques.

Al-Dhari, an outspoken critic of the government and the U.S. occupation, alleged that the Shiite-led government was using the 24-hour curfew as a way to carry out attacks against Sunnis, but he urged Iraqis not to be lured into more violence.

"Be patient and practice steadfastness and don't be lured into this sedition that aims to destroy" Iraq, he said.

In Baghdad, Ali al-Adib, a Shiite lawmaker close to al-Maliki, dismissed al-Dhari as a radical with few supporters. "If he doesn't want this elected national unity government what does he want, a return to dictatorship?" al-Adib said in an interview.