U.S. experts say the war also demonstrated the U.S. military's effectiveness in conventional operations, as seen in the "shock and awe" campaign, when U.S. forces steamrolled into Baghdad and overthrew Saddam's government in a matter of weeks.
But despite the initial success, an insurgency arose even as former Defense Secretary Donald Rumsfeld denied its existence.
Critics said the lack of planning for the after effects of the invasion was one of the worst strategic blunders the United States has ever made.
Christopher A. Preble, director of foreign policy studies at the Cato Institute, said there were plenty of warning signs that all would not go smoothly after the invasion.
"I'm a little frustrated by people saying we had no idea this would happen," he said. "Academics and scholars of nation building and post conflict reconstruction understood very well that the analogies to Japan and Germany after World War II were completely flawed."
Still, it had been many years since the United States had embarked a mission of this scale --full-on regime change -- and the Bush administration did not anticipate having to stay for that long.
"If a future president is serious about overthrowing a foreign government and replacing it with a government that we like better, it is going to be a long and costly enterprise," he said.
The war and its strategic failures have given way to an "Iraq syndrome" -- a reluctance to engage in regime change operations and post conflict stabilization and reconstruction, some analysts argued.
Americans want to move on, a sentiment mirrored in Obama' s speech on Tuesday when he jumped from the subject of Iraq to the U.S. economy, some analysts contended.
Michael E. O'Hanlon, senior fellow at the Brookings Institution, said the United States will in the future be less inclined to become involved in such conflicts.
Still, there may be future instances in which Washington is faced with making a decision on whether to use military force and may have few other choices but to go to war, he said.
But the most important lesson of Iraq is that planning for the after-effects of an invasion is necessary, he said.
"You can never assume that somehow order will spring up naturally out of chaos," he said.
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BEIJING, Sept. 1 (Xinhua) -- U.S. President Barack Obama announced Tuesday the end of combat operations in Iraq in an Oval Office address to the nation. There was a sense of symbolic "correction" for Obama as he announced the historic decision in exactly the same place where former president George W. Bush unleashed the U.S. war machine more than seven years ago, and a sense "reflection" permeated through his long address. Full story
U.S. vice president: Iraq close to form new gov't
BAGHDAD, Sept. 1 (Xinhua) -- U.S. Vice President Joe Biden said Wednesday that he believed Iraq was close to forming a new government after the parliamentary elections were held six months ago, an Iraqi television reported.
Biden was quoted by the al-Sharqya private channel as saying that he had met with everyone of the major leaders of the Iraqi groups that won portions of the vote in the elections, and he was convinced that they were close to forming a new government. Full story
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BEIJING, Sept.1(Xinhuanet) -- President Barack Obama has visited a military base in Texas as the US combat mission in Iraq formally came to an end.
At the Fort Bliss army post, home to several units that fought in Iraq, Obama expressed his deep gratitude to the troops. He praised the excellence of their mission in Iraq, saying, his greatest pride is in being their commander-in-chief. Full story
Special Report: Situation in Iraq
