The invasion of Iraq on March 20th 2003 went off very well. Saddam Hussein was eventually captured on December 14th 2003, tried for war crimes from 2004 to 2006 and abruptly hanged without US approval on December 30th 2006.
The weapons of mass destruction was the key political reason for the pre-emptive war on Iraq, but they have been removed by Saddam Hussein to another country so they could not be found.
The oil-for-food program has been instrumental in getting the United States cheap oil while construction of new oil pipelines are underway. In a way the United States might have lost personnel in casualties and the cost of the war in Iraq, but everything evens out in the end .