(AP) - The last U.S. soldiers rolled out of Iraq across the border to neighboring Kuwait at daybreak Sunday, whooping, fist bumping and hugging each other in a burst of joy and relief. Their exit marked the end of a bitterly divisive war that raged for nearly nine years and left Iraq shattered, with troubling questions lingering over whether the Arab nation will remain a steadfast U.S. ally.

The mission cost nearly 4,500 American and well more than 100,000 Iraqi lives and $800 billion from the U.S. Treasury. The question of whether it was worth it all is yet unanswered.

U.S. officials acknowledged the cost in blood and dollars was high, but tried to paint a picture of victory - for both the troops and the Iraqi people now free from tyranny and on a path for democracy. But gnawing questions remain: Will Iraqis be able to forge their new government amid the still stubborn sectarian clashes. And will Iraq be able to defend itself and remain independent in a region fraught with turmoil and still steeped in insurgent threats.

The soldiers left behind an Iraq free from the tyranny of Saddam Hussein, inching toward democracy and vowing to be a good neighbor in the region.

Many Iraqis, however, are nervous and uncertain about the future. Their relief at the end of Saddam, who was hanged on the last day of 2006, was tempered by a long and vicious war that was launched to find non-existent weapons of mass destruction and nearly plunged the nation into full-scale sectarian civil war.