A U.S. military convoy was patrolling the streets of southern Baghdad around 10 p.m. the night of March 23, 2008, when something went horribly wrong. A roadside bomb exploded near the soldiers' vehicle.

Pte. George Delgado, Pte. 1st Class Andrew J. Habsieger, Staff Sgt. Christopher M. Hake, and Specialist. Jose A. Rubio Hernandez were all killed in the ensuing carnage. Another U.S. soldier was injured in the attack.

With their deaths, the U.S. military marked a grim milestone. Less than a week after the fifth anniversary of the launch of Operation Iraqi Freedom, Americans mourned their country's 4,000th military death in the conflict. Almost 30,000 have been wounded.

The day after the four soldiers' deaths, U.S. President George Bush expressed his deep sympathies to the families of the fallen and praised the soldiers for their sacrifice.

"One day, people will look back at this moment in history and say, 'Thank God there were courageous people willing to serve, because they laid the foundations for peace for generations to come'," Bush said.

Fewer casualties than Vietnam, Korea

Future predictions aside, the current generation of Americans appears to have a more ambivalent view. According to one CBS News poll taken in early 2008, just three in 10 Americans approved of the way the Bush administration's handling of the Iraq war.

Compared to the rate of casualties, public support declined faster than during the Korean or Vietnam wars, according to a 2005 article in the journal Foreign Affairs by political science professor John Mueller of Ohio State University. Yet the casualty figures to date are lower than in other modern American wars.

In Vietnam, the U.S. lost on average about 4,850 troops a year from 1963-75. In the Korean war, from 1950-53, the U.S. lost about 12,300 soldiers a year.

A 2006 Duke University study found that it was 100 times as likely that an American knew one of the 292,000 Americans killed in the Second World War than someone today would know a service member slain in Iraq.

The attacks on Sept. 11, 2001, were the basis of most of the American backing of the invasion of Iraq, but as the Bush administration changed its reasons for the invasion — from weapons of mass destruction and Iraqi connections to al-Qaeda to bringing diplomacy to the region — skepticism among Americans about the conflict was reflected in dropping support for the war in the polls.

In March 2004, a Gallup poll found that 65 per cent of Americans supported the decision to fight a war in Iraq. A year and a half later, that support had dropped to 44 per cent and fell further to 36 per cent in the March 2008 CBS News poll.

Despite the apparent public displeasure, by the time of the 4,000th death, the war was further out of the American public's focus, replaced by worries over domestic economic decline. Whether Iraq will again emerge as an issue during the U.S. presidential campaign remains to be seen.

Losses on all sides

Almost 97 per cent of U.S. military deaths have occurred since Bush declared an end to major combat operations in May 2003. When the president made that announcement, under a "Mission Accomplished" banner aboard the USS Abraham Lincoln warship, 138 American soldiers had died.

The deadliest year for the American military was 2007, with 901 deaths recorded. That was 51 more deaths than in 2004, the second deadliest year for U.S. soldiers.

A major cause of the 2007 increase was the "surge" operation, announced by Bush in January of that year, to regain control of Baghdad and surrounding areas. The surge added 30,000 soldiers to the conflict, bringing troop levels up to about 158,000 as of March 2008.

Tens of thousands of Iraqi civilians also have been killed since the U.S.-led invasion on March 20, 2003, although estimates of a specific figure vary widely because of the difficulty in collecting accurate information.

One widely respected tally by the organization Iraq Body Count, which collects figures based mostly on media reports, estimates, as of April 2, 2008, that 82,725 to 90,251 Iraqi civilians have lost their lives in the conflict.

With files from the Associated Press

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