As part of the global war on terror, the United States and its allies invaded Iraq in March 2003 and subsequently overthrew the regime of Iraqi dictator Saddam Hussein. The U.S.-led coalition’s military campaign was swift and decisive, and its forces captured Baghdad, Iraq’s capital, on April 9. The first phase of the Iraq War ended on April 30. However, violence in Iraq expanded dramatically over the next few years as the country descended into a multifaceted civil war between rival groups. The collapse of the regime created a vacuum as police officers and other security officials were removed from their posts or left their positions.