The war on terror, officially the Global War on Terrorism (GWOT), is a global military campaign initiated by the United States in response to the September 11 attacks in 2001. A global conflict spanning multiple wars, some researchers and political scientists have argued that it replaced the Cold War.
The main targets of the campaign were militant Islamist movements such as al-Qaeda, the Taliban and their allies. Other major targets included the Ba'athist regime in Iraq, which was deposed in an invasion in 2003, and various militant factions that fought during the ensuing insurgency. Following its territorial expansion in 2014, the Islamic State also emerged as a key adversary of the United States.