How is invading Afghanistan against the constitution?<p>&gt;even though neither country attacked the U.S<p>Afghanistan attacked the US by allowing an terrorist group who declared war on America plot an attack on the United States from their country.<p>&gt;and therefore attacking both of them was a U.N. Charter violation, which we are of course signatories to.<p>The UN Charter allows for self defense AND the UN authorized the attacks. In fact the ISAF is a UN operation.