The US-led invasion of Iraq resulted in significant lessons, including the mistake of going to war based on faulty intelligence, problematic occupation and nation-building efforts, and immense costs and the toll on democracy.
The Iraq War, which began in 2003 as a US-led invasion, resulted in several lessons that should be learned to prevent future blunders. The decision to go to war was the initial and most significant mistake, based on faulty intelligence, with groupthink further compounding the error. Occupation and nation-building efforts were also problematic, with the decision to withdraw in 2011 being problematic as well. The costs of the Iraq War have been immense, including loss of life and enormous financial costs. The toll on democracy has also been significant, with an erosion of public confidence and a lack of accountability.