The following are events related to the Global War On Terrorism (GWOT) that took place on this day.

2001

• President Bush addresses the nation, announcing war and stating: “The United States of America will use all our resources to conquer this enemy. We will rally the world. We will be patient. We’ll be focused, and we will be steadfast in our determination. This battle will take time and resolve, but make no mistake about it, we will win.”
• For the first time ever, Marine aviators made combat air patrols in the skies over the Unites States. Washington, D.C. was guarded by F/A-18 Hornets flown by pilots from Marine Fighter Attack Squadron 321 based out of Andrews Air Force Base in southern Maryland. The Marine pilots flew the patrols to give a days respite to the Washington Air National Guard, which had flown the patrols on 11 September, and resumed command of the mission on 13 September.
• U.S. Central Command begins planning for military strikes against al-Qaeda
  and the Taliban in Afghanistan.

2007

• Operation California in Iraq

Casualties on September 12:

• BENNETT, WILLIAM MONROE – September 12, 2003
• MOREHEAD, KEVIN NEIL – September 12, 2003
• POINDEXTER, JASON TOWNER – September 12, 2004
• WETHERBEE, ALEXANDER EDMUND – September 12, 2004
• MACRUM, ROBERT DOUGLAS – September 12, 2005
• PEREZ, EMILY JAZMIN TATUM – September 12, 2006
• FREIWALD, JASON RICHARD – September 12, 2008
• MARCUM, JOHN WAYNE – September 12, 2008
• ALLEN, NEKL BRUCE – September 12, 2009
• BERKY, BRYAN DAVID – September 12, 2009
• COX, DANIEL LEE – September 12, 2009
• HORNBARGER, JAMES ROBERT – September 12, 2009
• JUDEN, TYLER AUSTIN – September 12, 2009
• THORNSBURY, DUANE ANTHONY – September 12, 2009
• PHAN, JASON KHAI – September 12, 2020