2003–2006 phase of the Iraqi insurgency
…until the United States left in 2011. The 2003–2006 phase of the Iraqi insurgency lasted until early 2006, when it escalated from an insurgency to a Sunni-Shia civil war, which became the most violent phase of the Iraq War. A number of factors played into the beginning of the insurgency in Iraq. Invading U.S.-led forces…