After the 9/11 aerial attacks on the World Trade Center and Pentagon killed 3,000 people, 19 al-Queda hijackers among them, the United States and “a Coalition of the Willing” launched a Global War on Terror (currently Overseas Contingency Operation) against terrorist states and organizations, including Afghanistan's Taliban regime and al-Queda (2001–2014) and Iraq (2003–2011).

These wars fueled not only political controversy but also high costs in blood and treasure. By 2011, in the War in Afghanistan there were 10,960 to 49,600 Afghan deaths and 22,291 injuries; 3,075 coalition deaths and 5,757 injuries; 1,933 US deaths and 16,854 injuries. In the same year, The War in Iraq saw 62,570 to 1,124,000 Iraqi deaths and an estimated equal number of injuries; 4,799 coalition deaths and more than 100,000 injuries; 3,988 US deaths and 25,819 injuries. US military and civilian expenditures totaled $2.7 trillion. Many observers feared that federal antiterrorist policies were undermining civil liberties and the human rights of enemy combatants.