Final answer:
In 2003, the notable event was the U.S. invasion of Iraq called Operation Iraqi Freedom, not the freeing of Saddam Hussein, a truce between militias, or a descent into civil war.
Step-by-step explanation:
In 2003, the significant event that took place was the U.S.-led invasion of Iraq, referred to as Operation Iraqi Freedom. President George W. Bush and his administration launched this operation without a formal declaration of war. On May 1, 2003, President Bush, aboard the USS Abraham Lincoln, declared that "major combat operations in Iraq have ended" against a backdrop of a "Mission Accomplished" banner, even though the situation in Iraq was far from stable. Subsequent to the invasion, Saddam Hussein was captured by the coalition forces and later tried and executed by an Iraqi court. It was not until later that Iraq descended into severe civil strife.