The memory of a burning Baghdad in the early hours of March 20, 2003 is still fresh, but most people could not have imagined that the Pandora's box would be opened at precisely the same moment as the American preemptive strike.
Five years on, the world's one and only superpower has not found a tangible way to reconstruct the war-ravaged country and a viable exit from it.
Looking back at the costs, most Americans have realized that the sheer demonstration of power, or what some consider a retaliation for the September 11 terror attacks, is not cheap or easy, in light of the rapid flow of military expense, the heart-breaking bloodshed, and the die-hard insurgence in Iraq.
In March 2008, an ABC News/Washington Post poll shows that 63 percent of Americans feel the war was not worth fighting, and only a slight majority of Americans, 53 percent, believe the US effort in Iraq will one day succeed.
At the start of the war, the United States spent some 4.4 billion US dollars a month on military operations in Iraq. In 2007, the budget jumped to some 8.4 billion dollars a month.
According to latest estimates, America's financial costs would rise above 650 billion dollars by 2008, on their way to perhaps 2 trillion if the commitment continues for another five years.
More heavy is the human cost. A total of 3,990 US troops have fallen in Iraq since the war started, and over 29,000 soldiers have been wounded.
Beyond that, the Iraqi people were living in a deeper quagmire.
Some 82,000 Iraqi civilians have been killed and a million or more are living as refugees in neighboring Arab countries.