Despite a Security Council mandate for action, Washington has chosen instead to rely on its right of self-defence. It is this area that has seen the most dramatic change in the current conflict – states that support terror groups may now themselves be legally attacked.
There were at least four possible legal justifications for the use of force against Afghanistan following the terrorist attacks of September 11: Chapter VII of the UN Charter, intervention by invitation, humanitarian intervention and self- defence. But the United States has relied solely on the last of these.