In 2000 , Republican George W. Bush was elected president in one of the closest and most controversial elections in U.S. history . Early in his term , his administration approved education reform and a large across-the-board tax cut aimed at stimulating the economy . Following the September 11 attacks in 2001 , the U.S. embarked on the Global War on Terrorism , starting with the 2001 war in Afghanistan . In 2003 , the U.S. invaded Iraq , which deposed the controversial regime of Saddam Hussein but also resulted in a prolonged conflict that would continue over the course of the decade . The Homeland Security Department was formed and the controversial Patriot Act was passed to bolster domestic efforts against terrorism . In 2006 , criticism over the handling of the disastrous Hurricane Katrina ( which struck the Gulf Coast region in 2005 ) , political scandals , and the growing unpopularity of the Iraq War helped the Democrats gain control of Congress . Saddam Hussein was later tried , charged for war crimes and crimes against humanity , and executed by hanging . In 2007 , President Bush ordered a troop surge in Iraq , which ultimately led to reduced casualties
September 11 attacks
September 11 attacks
History of the United States (1991–2008)