IMMANUEL KANT, PERPETUAL PEACE: A PHILOSOPHICAL SKETCH (1795)
Whether this satirical inscription on a Dutch innkeeper's sign upon which a burial ground was painted had for its object mankind in general, or the rulers of states in particular, who are insatiable of war, or merely the philosophers who dream this sweet dream, it is not for us to decide. But one condition the author of this essay wishes to lay down. The practical politician assumes the attitude of looking down with great self-satisfaction on the political theorist as a pedant whose empty ideas in no way threaten the security of the state, inasmuch as the state must proceed on empirical principles; so the theorist is allowed to play his game without interference from the worldly-wise statesman. Such being his attitude, the practical politician (and this is the condition I make) should at least act consistently in the case of a conflict and not suspect some danger to the state in the political theorist's opinions which are ventured and publicly expressed without any ulterior purpose. By this clausula salvatoria the author desires formally and emphatically to deprecate herewith any malevolent interpretation which might be placed on his words.
SECTION I: CONTAINING THE PRELIMINARY ARTICLES FOR PERPETUAL PEACE AMONG
1. "No Treaty of Peace Shall Be Held Valid in Which There Is Tacitly Reserved Matter for a Future War";
Otherwise a treaty would be only a truce, a suspension of hostilities but not peace, which means the end of all hostilities, so much so that even to attach the word "perpetual" to it is a dubious pleonasm. The causes for making future wars (which are perhaps unknown to the contracting parties) are without exception annihilated by the treaty of peace, even if they should be dug out of dusty documents by acute sleuthing. When one or both parties to a treaty of peace, being too exhausted to continue warring with each other, make a tacit reservation (reservatio mentalis) in regard to old claims to be elaborated only at some more favourable opportunity in the future, the treaty is made in bad faith, and we have an artifice worthy of the casuistry of a Jesuit. Considered by itself, it is beneath the dignity of a sovereign, just as the readiness to indulge in this kind of reasoning is unworthy of the dignity of his minister.But if, in consequence of enlightened concepts of statecraft, the glory of the state is placed in its continual aggrandisement by whatever means, my conclusion will appear merely academic and pedantic.
2. "No Independent States, Large or Small, Shall Come under the Dominion of Another State by Inheritance, Exchange, Purchase, or Donation"
A state is not, like the ground which it occupies, a piece of property (patrimonium). It is a society of men whom no one else has any right to command or to dispose except the state itself. It is a trunk with its own roots. But to incorporate it into another state, like a graft, is to destroy its existence as a moral person, reducing it to a thing; such incorporation thus contradicts the idea of the original contract without which no right over a people can be conceived. 
Everyone knows to what dangers Europe, the only part of the world where this manner of acquisition is known, has been brought, even down to the most recent times, by the presumption that states could espouse one another; it is in part a new kind of industry for gaining ascendancy by means of family alliances and without expenditure of forces, and in part a way of extending one's domain. Also the hiring-out of troops by one state to another, so that they can be used against an enemy not common to both, is to be counted under this principle; for in this manner the subjects, as though they were things to be manipulated at pleasure, are used and also used up.
3. "Standing Armies (miles perpetuus) Shall in Time Be Totally Abolished";
For they incessantly menace other states by their readiness to appear at all times prepared for war; they incite them to compete with each other in the number of armed men, and there is no limit to this. For this reason, the cost of peace finally becomes more oppressive than that of a short war, and consequently a standing army is itself a cause of offensive war waged in order to relieve the state of this burden. Add to this that to pay men to kill or to be killed seems to entail using them as mere machines and tools in the hand of another (the state), and this is hardly compatible with the rights of mankind in our own person. But the periodic and voluntary military exercises of citizens who thereby secure themselves and their country against foreign aggression are entirely different.
The accumulation of treasure would have the same effect, for, of the three powers (the power of armies, of alliances, and of money) the third is perhaps the most dependable weapon. Such accumulation of treasure is regarded by other states as a threat of war, and if it were not for the difficulties in learning the amount, it would force the other state to make an early attack.
4. "National Debts Shall Not Be Contracted with a View to the External Friction of States";
This expedient of seeking aid within or without the state is above suspicion when the purpose is domestic economy (e.g., the improvement of roads, new settlements, establishment of stores against unfruitful years, etc.). But as an opposing machine in the antagonism of powers, a credit system which grows beyond sight and which is yet a safe debt for the present requirements (because all the creditors do not require payment at one time) constitutes a dangerous money power. This ingenious invention of a commercial people [England] in this century is dangerous because it is a war treasure which exceeds the treasures of all other states; it cannot be exhausted except by default of taxes (which is inevitable), though it can be long delayed by the stimulus to trade which occurs through the reaction of credit on industry and commerce. This facility in making war, together with the inclination to do so on the part of rulers--an inclination which seems inborn in human nature - is thus a great hindrance to perpetual peace. Therefore, to forbid this credit system must be a preliminary article of perpetual peace all the more because it must eventually entangle many innocent states in the inevitable bankruptcy and openly harm them. They are therefore justified in allying themselves against such a state and its measures.
5. "No State Shall by Force Interfere with the Constitution or Government of Another State";
For what is there to authorise it to do so? The offense, perhaps, which a state gives to the subjects of another state? Rather the example of the evil into which a state has fallen because of its lawlessness should serve as a warning. Moreover, the bad example which one free person affords another as a scandalum acceptum is not an infringement of his rights. But it would be quite different if a state, by internal rebellion, should fall into two parts, each of which pretended to be a separate state making claim to the whole. To lend assistance to one of these cannot be considered an interference in the constitution of the other state (for it is then in a state of anarchy). But so long as the internal dissension has not come to this critical point, such interference by foreign powers would infringe on the rights of an independent people struggling with its internal disease; hence it would itself be an offense and would render the autonomy of all states insecure.
6. "No State Shall, during War, Permit Such Acts of Hostility Which Would Make Mutual Confidence in the Subsequent Peace Impossible: Such Are the Employment of Assassins (percussores), Poisoners (venefici), Breach of Capitulation, and Incitement to Treason (perduellio) in the Opposing State";
These are dishonourable stratagems. For some confidence in the character of the enemy must remain even in the midst of war, as otherwise no peace could be concluded and the hostilities would degenerate into a war of extermination (bellum internecinum). War, however, is only the sad recourse in the state of nature (where there is no tribunal which could judge with the force of law) by which each state asserts its right by violence and in which neither party can be adjudged unjust (for that would presuppose a juridical decision); in lieu of such a decision, the issue of the conflict (as if given by a so-called "judgement of God") decides on which side justice lies. But between states no punitive war (bellum punitivum) is conceivable, because there is no relation between them of master and servant.
It follows that a war of extermination, in which the destruction of both parties and of all justice can result, would permit perpetual peace only in the vast burial ground of the human race. Therefore, such a war and the use of all means leading to it must be absolutely forbidden. But that the means cited do inevitably lead to it is clear from the fact that these infernal arts, vile in themselves, when once used would not long be confined to the sphere of war. Take, for instance, the use of spies (uti exploratoribus). In this, one employs the infamy of others (which can never be entirely eradicated) only to encourage its persistence even into the state of peace, to the undoing of the very spirit of peace.
Although the laws stated are objectively, i.e., in so far as they express the intention of rulers, mere prohibitions (leges prohibitivae), some of them are of that strict kind which hold regardless of circumstances (leges strictae) and which demand prompt execution. Such are Nos. 1, 5, and 6. Others, like Nos. 2, 3, and 4, while not exceptions from the rule of law, nevertheless are subjectively broader (leges latae) in respect to their observation, containing permission to delay their execution without, however, losing sight of the end. This permission does not authorise, under No. 2, for example, delaying until doomsday (or, as Augustus used to say, ad calendas Graecas) the re-establishment of the freedom of states which have been deprived of it - i.e., it does not permit us to fail to do it, but it allows a delay to prevent precipitation which might injure the goal striven for. For the prohibition concerns only the manner of acquisition which is no longer permitted, but not the possession, which, though not bearing a requisite title of right, has nevertheless been held lawful in all states by the public opinion of the time (the time of the putative acquisition).
See Immanuel Kant Perpetual Peace: A Philosophical Sketch <http://www.mtholyoke.edu/acad/intrel/kant/kant1.htm>
Or Perpetual Peace: A Philosophical Sketch by Immanuel Kant 1795
Supplied by Francis K Krause 11th September 2002