Washington ? With a fearsome military barrage dubbed “shock and awe,” the war in Iraq began one year ago today with a blitz of cruise missiles raining down on Baghdad followed by waves of troops blazing a swift path to victory.

In conventional military terms, the U.S.-led invasion was a stunning success, a showcase for mobile forces brandishing the most technologically advanced weaponry. Americans and many Iraqis celebrated when statues of tyrant Saddam Hussein toppled to the ground a mere four weeks later.

Yet now, one year after the first airstrikes, Americans remain divided about the wisdom of launching into a war that never really ended. Frustrated by continuing bursts of violence, burdened by costs reaching beyond $123 billion and saddened by the ongoing loss of life, many Americans believe their government misled them into fighting a needless war.

Was it worth all the costs and the bloodshed? Polls show that a bare majority of Americans say yes, and that most people in other nations say no.

The costs also have contributed to a record federal deficit. The occupation has strained the armed services. And the human toll, marked by almost-daily casualties and prolonged duty in a hostile environment, has undercut the morale of soldiers and their families. During the past year, 571 U.S. military personnel have been killed and 2,825 wounded.

At the same time, much of Iraq remains in chaos. Basic services, such as electricity and water supplies, are only now reaching prewar levels. And a bloody insurgency puts occupying soldiers, civilians and aid workers in constant peril.

Since the invasion, American forces have been unable to find clear evidence of weapons of mass destruction, and Iraq’s links to terrorist groups remain unproven and debatable. Increasingly, President Bush and other supporters of the war are emphasizing the third motive — a war of liberation — as justification for the invasion.

Historians and those who take the public pulse say the judgment of history will depend on whether the war ultimately makes America safer, and on whether it leads to a stable and democratic Iraq that does not pose threats leading to yet another war.

“It won’t be remembered as a popular war,” predicted Jack Tunstall, military history expert at University of South Florida. “The American people want instant results, and what did we see? We were told that once we have Hussein, it’s all over. It didn’t happen. So the question becomes, why did they invade Iraq? And the second question is, why are we still there?”