Iraq War

The Iraq War began in March 2003 when a United States-led coalition invaded Iraq to remove Saddam Hussein's government, justified chiefly by claims that Iraq possessed weapons of mass destruction that were never subsequently found. Coalition forces achieved a rapid conventional victory, capturing Baghdad within weeks and toppling Saddam Hussein's government by April 2003, but the occupation that followed gave way to a prolonged and increasingly sectarian insurgency between Sunni and Shia armed groups alongside continued attacks on coalition forces. The United States responded to escalating violence with a troop surge in 2007 under General David Petraeus, which combined with new counterinsurgency tactics and local Sunni tribal alliances to significantly reduce violence in subsequent years. American combat forces formally withdrew from Iraq in December 2011, though the country's instability persisted afterward and contributed to conditions that allowed the emergence of the Islamic State insurgency in Iraq later in the decade.