Following the 9/11 attacks, the US declared a war on terrorism, principally aimed at Al Qaeda. The declaration could be dismissed as a sleight of words were it not for the fact that, for the US and for those it affects, it has real and serious legal consequences. The US claims that its declaration of a war on terror is merely an act of self-defence as in its view, Al Qaeda declared a state of war through the 9/11 attacks and these initiated an armed conflict to which the laws of armed conflict apply. Although the characterization of the war on terror as an armed conflict has been rejected by many authorities, the view that the 9/11 attacks were an armed attack giving rise to the rise of self-defence has been widely accepted.

If the 9/11 attacks are armed attacks giving rise to the right of self-defence but the attacks did not constitute an armed conflict; as an act of war, they would not be subject to the laws of war. This would disconnect jus ad bellum and jus in bello in relation to acts of war. If there is a state of war without there being an armed conflict, this would allow the US to take certain measures in relation to the terrorist threat but would not give it the more extensive liberties associated with an actual wartime situation.