In War Powers Bill I described the provisions of the Defence Amendment (Parliamentary Approval of Overseas Service) Bill [No. 2], which was introduced into the Senate by Western Australian Greens Senator Scott Ludlam in February 2008, and is currently the subject of an inquiry by a Senate Committee.
On the face of it the provisions of the Bill seem sound, but as the power to make war is the central issue of national security, examining the feasibility of transferring the war-making power from the Executive to the Parliament will require the undertaking of a number of thought experiments to see whether it works under all conceivable circumstances.
One issue which will require careful consideration in that regard is how any decision to undertake an act of pre-emptive self-defence might be transacted through the Parliament.
The international law concerning the right of anticipatory self-defence was built upon the issues raised by the Caroline Affair, which strained relations between the United States and the United Kingdom for five years commencing in 1837. In that year, a group of Canadian rebels, led by William Lyon Mackenzie, sought to establish a Canadian republic. After their rebellion in Upper Canada (now Ontario) failed, they fled to the United States. They took refuge on Navy Island in the Niagara River, which forms the boundary between Ontario and New York State, and declared themselves the Republic of Canada. American sympathizers supplied them with money, provisions, and arms via the steamboat SS Caroline.
On 29 December, Canadian loyalist officers commanding a party of militia crossed the border and seized the Caroline, towed her into the current, set her on fire and cast her adrift over Niagara Falls. A black American was killed in the process of seizing her.
American public opinion was outraged and there were several acts of retaliation, notably the burning of the SS Sir Robert Peel while it was in American waters, and the murder of a loyalist Canadian captain who had been involved in the incident.
The matter was finally resolved during the negotiation by United States Secretary of State Daniel Webster and U.K. Privy Counsellor Alexander Baring, 1st Lord Ashburton, of a treaty which resolved several outstanding issues concerning the United States – Canadian border (the Webster – Ashburton Treaty). In the course of their negotiations in 1842 Webster admitted that the use of force might have been justified by the necessity of self-defence, but denied that such a necessity existed. Lord Ashburton argued that the circumstances provided excuse for what was done, but apologised for the invasion of American territory.
In a note dated 24 April 1841 to the British Minister in Washington, Mr Fox, subsequently conveyed directly to Lord Ashburton, Secretary of State Daniel Webster set out the principles on which the principle of anticipatory self-defence has subsequently been established in international law:
... it will be for Her Majesty's Government to show, upon what state of facts, and what rules of national law, the destruction of the “Caroline” is to be defended. It will be for that Government to show a necessity of self-defence, instant, overwhelming, leaving no choice of means, and no moment for deliberation. It will be for it to show, also, that the local authorities of Canada,- even supposing the necessity of the moment authorized them to enter the territories of the United States at all,-did nothing unreasonable or excessive; since the act justified by the necessity of self-defence, must be limited by that necessity, and kept clearly within it. It must be strewn that admonition or remonstrance to the persons on board the "Caroline" was impracticable, or would have been unavailing; it must be strewn that daylight could not be waited for; that there could be no attempt at discrimination, between the innocent and the guilty; that it would not have been enough to seize and detain the vessel; but that there was a necessity, present and inevitable, for attacking her, in the darkness of the night, while moored to the shore, and while unarmed men were asleep on board, killing some, and wounding others, and then drawing her into the current, above the cataract, setting her on fire, and, careless to know whether there might not be in her the innocent with the guilty, or the living with the dead, committing her to a fate, which fills the imagination with horror. A necessity for all this, the Government of the United States cannot believe to have existed.
The Caroline Affair has been used to establish the principal of “anticipatory self-defence” in international law. The principle holds that pre-emptive action may be justified only in cases where the "necessity of that self-defence is instant, overwhelming, and leaving no choice of means, and no moment for deliberation”. It is well established that to be a valid use of force in terms of self-defence under international customary law, there is a need that it be immediate, proportionate and necessary.
It is clear that the rights available under the customary law which flows from the Caroline Affair can only be invoked within very narrow confines. Defendants at Nuremberg sought to invoke them as a defence in relation to the invasions of Denmark and Norway, but the International Military Tribunal was not impressed.
Actions described as “defensive” since the Second World War, such as the invasion of Afghanistan, would be very difficult to justify under the Caroline principles, and would appear to be more in the nature of retaliation than anticipatory self-defence.
Circumstances fitting the Caroline principles would seem to arise so rarely, and when they do arise to do so with such immediacy, that they would be unlikely to present insuperable difficulties in relation to the proposed transfer of the war-making power to the Parliament. This is, nevertheless, an issue that needs to be considered.