Today we make war on many things. Obesity. Drugs. Want. Terror. In none of these cases is it an abuse of language to talk of a state making “war” upon an abstract thing.
In international law, however, “war” has a particular meaning. It is “a contention between two or more States through their armed forces, for the purpose of overpowering each other and imposing such conditions of peace as the victor pleases.” Are we (and other States) at war with Da’esh?
No, we are not. Da’esh, ISIS, ISIL or IS is not a State, and so we cannot be in a state of war with it. (That Da’esh self styles itself a ‘State’ does not make it one. Actual States have enough self-confidence not to label themselves as such. Jamaica is just Jamaica, Portugal is just Portugal, and so on.)
Today, the UN Charter prohibits all use of force in another state that is not in self defence, carried out with Security Council authorisation, or with that other state’s consent. The operative phrase here is ‘use of force’ not ‘war’. In the modern era ‘war’itself has diminished legal significance.
When President Hollande declared that France is ‘at war’ with Da’esh, and President Obama stated that the United States is ‘at war’ with terrorists, they are not abusing language. However, they may be criticised for conferring a legitimacy upon Da’esh that they do not possess, by implying that they are a State. It is to the United Kingdom government’s credit that the motion in favour of military action in Syria, and the Prime Minister’s speech in support of it, did not refer to ‘war’.
Whether we are at war is legally significant within the United States. Article I, Section 8, Clause 11 of the United States Constitution states
The Congress shall have power…
To declare war.
The President, by contrast, is given the power to direct the military under Article II, section 2 as Commander in Chief of the armed forces.
It is at least arguable that although Congress has been given the power to declare war, that does not require Congressional authorisation for all uses of force by the military, either within the United States or abroad. If a friendly state seeks United States military support in suppressing criminals, that does not require any declaration of war. Congress has been given a particular power in international affairs. The choice over the momentous decision of whether to go to war with another State. Luckily we are not. Although Congress passed the War Powers Resolution in 1973, which requires that the President communicate to Congress the committal of troops within 48 hours, and the removal of all troops after 60 days if Congress has not granted an extension, on its own this cannot have altered the Constitutional division of power between legislature and executive.
That Congress’ has the exclusive power to declare war, but not the exclusive power to use force, should be obvious from the history of the United States. When Japan attacked the United States at Pearl Harbor the use of force in defence did not require Congressional approval. If President Roosevelt had sought to declare war on Japan or Germany in advance of attack he could not unilaterally have done so.
Regardless of the above, it would be politically appropriate if Congress debated the military action in Syria and Iraq as the UK Parliament has done. That it has not, because of the fears of the divisions this would reveal, is not to its credit.