Article 2, paragraph 3 of the UN Charter requires that:
All Members shall settle their international disputes by peaceful means in such a manner that international peace and security and justice are not endangered. The UN General Assembly, in adopting its 1982 Manila Declaration on the Peaceful Settlement of Disputes, emphasized the need to exert utmost efforts to settle any conflicts and disputes between States exclusively by peaceful means'' and that'' the question of the peaceful settlement of disputes should represent one of the concerns for States and the United Nations''. In the age of nuclear weapons, the importance of the principle of peaceful settlement of international disputes is apparent.

International Dispute:

In the Mavromattes case, the PCIJ defined a dispute as 'a disagreement on a point of law or fact, a conflict of legal views or interests between two persons'' (Greece v U.K), J.G. Merrills suggests that:
A dispute may be defined as a specific disagreement concerning a matter of fact, law, or policy in which a claim or assertion of one party is met with refusal, counterclaim, or denial by another. In the broadest sense, an international dispute can be said to exist whenever such a disagreement involves governments, institutions, juristic persons (corporations), or private individuals in different parts of the World. However, the disputes with which the present work is primarily concerned are those in which the parties are two or more of the hundred and sixty or so sovereign states into which the world is currently divided.

Article 2(3) of the UN Charter provides:

All Members shall settle their international disputes by peaceful means in such a manner that international peace and security, and justice, are not endangered.

Article 33 of the UN Charter provides:

1. The parties to any dispute, the continuance of which is likely to endanger their maintenance of international peace and security, shall, first of all, seek a solution by negotiation, inquiry, mediation, conciliation, arbitration, judicial settlement, resort to regional agencies or arrangements, or other peaceful means of their own choice.
2. The Security Council shall, when it deems necessary, call upon the parties to settle their disputes by such means.

Pacific settlement of the dispute

Chapter VI (Articles 33-37) of the UN Charter, entitled Pacific Settlement of Disputes establishes further obligations of the parties and various dispute settlement powers of the Security Council. Under Article 35, any state may bring any dispute to the attention of the Security Council or the General Assembly.

Under Article 36, the SC may, at any stage of a dispute the continuance of which is likely to endanger the maintenance of international peace or security, recommend appropriate procedures or methods of adjustments; in doing so, the SC should take into consideration that legal disputes should be as a general rule be referred by the parties to the International Court of Justice.

Article 37 provides that, should the parties to a dispute of nature referred to in Article 33 fail to settle it by the means indicated in Article 33, they shall refer it to SC which, if it deems that the continuance of the dispute is, in fact, likely to endanger the maintenance of international peace and security, shall decide whether to take action under Article 36 or to recommend such terms of settlement as it may consider appropriate.

Article 38 provides that:
Without prejudice to the provisions of Article 33 to 37, the Security Council may, if all the parties to any dispute so request, make recommendations to the parties with a view to a pacific settlement of the dispute.

The links between the principle of the peaceful settlement of disputes and other specific principles of international law are highlighted both in the friendly relations declaration and in the Manila Declaration, as follows:

1. The principle of non-use of force in international relations.
2. The principles of non-intervention in the internal affairs or external affairs of states.
3. Principles of equal rights and self-determination of people.
4. Principles of the sovereign equality of states.
5. Principles of international law concerning the sovereignty, independence, and territorial integrity of states.
6. Good faith in international relations.
7. Principles of justice and international law.

The means listed in Article 33 of the charter are:

1. Negotiation: – The settlement of the international disputes by the disputant states themselves by negotiation is said to be the settlement of the disputes by negotiation. In other words, when there a dispute arises between two or more states then to avoid the chances of war or violence they tend to negotiate for the matters to be settled. The negotiation is to be taken by the political representatives of the disputant countries, without involving any third or non-concerned country.
    
2. Good-offices: – The act or arrangements taken by a third party to bring disputant parties for negotiation or to settle a dispute between them by any peaceful means is said to be Good-offices. In the case of Good-offices, the third merely renders services to bring the disputant parties to peace full means of settlement of disputes. Here the third party does not give any suggestions or take part in the meetings as to be held between the disputant parties. Shortly speaking, in case of good offices whenever the parties to dispute come to peace full of the settlement of dispute the duty of the third party finishes.
    
3. Mediation: – The act of participating and in the discussions and giving suggestions to settle a dispute between two parties by a third party is said to Mediation. In other words, mediation is the method to settle a dispute where any third party actively takes part in the sessions of dialogues or negotiations held between the disputant party to resolve the dispute. In the case of mediation, the mediator should consider the matter of compromise between the parties rather than encourage the strict letter of the law.
    
4. Inquiry: – The process to ascertain the facts of disputes by a commission of imperial investigators is said to the inquiry. This mean is intended to find out the questions of law and mixed questions of law and fact involved in a dispute. The only function of the commission is to bring in light those facts, which are the root cause for the alleged dispute, and to investigate the question of law and mixed questions of law and fact.
    
5. Conciliation: – The process of referring a dispute to a commission; to find out facts and prepare a report containing proposals for the settlement of that dispute, is called conciliation. In case of conciliation, the commission is to take two tasks, at first, it shall ascertain the facts of the dispute and secondly, it shall prepare a report which shall reveal that the possible measures to settle the dispute. But the proposals prepared by the commission have no binding force upon the parties. The parties can disagree with the proposals.
    
6. Arbitration: – The process of referring the dispute; by the mutual consent of the parties to a body of persons or a tribunal for a legal decision is called arbitration. The essential ingredient of arbitration is the consent of disputant parties to the dispute. In other words, the referring of the dispute to a Court of Arbitration is dependent on the sweet-well of the parties. International law recognizes a court for arbitration known as the Permanent Court of Arbitration. But in fact, it is neither permanent nor a court.
    
7. Judicial Settlement: – The process of settling a dispute; by the International Tribunal in the light of the provisions of International Law, is said to be Judicial Settlement. For Judicial Settlement there is a judicial organ in international law, known as the International Court of Justice. Both the award given by the arbitration tribunal and decision given by the International Court of Justice comes in the ambit of Judicial Settlement. Like in arbitration, in case of referring the dispute to the International Court of Justice the consent of both the parties are necessary to be given. International Court of Justice shall take its proceeding in the light of the rules of International law, and its procedure is governed by the statute known as the Statute of the International Court of Justice. International Court of Justice plays a very important rule in the settlement of international disputes.
    
8. Security Council: – A dispute may be settled by a principal organ of the United Nations, known as the Security Council. The Council consists of fifteen members. Five members are permanent while the remaining ten members are non-permanent members. Wide powers have been entrusted to the Council for the settlement of the disputes, which tend to endanger world peace and security. There are several measures to be taken by the Council for the settlement of the disputes.
    
9. General Assembly: – General Assembly is another principal organ of the United Nations. The Assembly has no specific means to settle the dispute, rather it has general powers to settle the international dispute. It has the power to discuss and to suggest better means for the peaceful settlement of the disputes.

Compulsive or Coercive Means

Compulsive or coercive means for the settlement of disputes are non-peaceful methods. Such measures involve pressure or force on a State to settle the dispute. However, the use of compulsive measures does not mean the use of armed forces in all cases. Normally, they include the measures which are just predecessor to war, or short of war.

Retorsion:

Retorsion is the technical term for retaliation. It is based, to some extent, on the principle of tit for tat. When an act is done by a State similar to that done earlier by another state, it is called Retorsion.

The purpose of Retorsion is to take retaliation. The acts which are done by a State in Retorsion are not illegal. In other words, they are permitted under International Law. However, it is an unfriendly act and in given circumstances, it may be an effective tool of law enforcement.

This is acknowledged in practice when international conventions sometimes provide for the employment of an unfriendly act as a reaction to the breach of obligation. The cases where Retorsion are employed as a means to settle the disputes may be numerous. For instance, if the citizens of a State are given unfair treatment in another State through rigorous passport regulations, the former may also make similar rigorous rules in respect of the citizens of the latter State.

One of the cases of the Retorsion took place in December 1992, when two Pakistani High Commission officials were declared persona non grata by India, Pakistan also expelled three Indian officials and declared them persona non grata. The action of Pakistan can be termed as Retorsion.

Reprisals:

The term reprisals includes the employment of any coercive measures by a State to secure redress. Thus, the main purpose of the reprisals is to compel the delinquent State to discontinue the wrongdoing, or to pursue it, or both. If a dispute has arisen due to an unjustified or illegal act of a State, the other state may take any coercive measure against that State to settle the dispute. Formerly, Reprisals were restricted only to the seizure of the property or persons, but later, it included other methods as well such as bombardments, the occupation of territories of a State, seizure of ships, freezing of assets of its citizens and taking any kind of property belonging to it.

Thus, it may be applied not only to the state but against the citizens of that State as well.
While a state is at liberty to take action of reprisal, but it has to meet some lawful conditions laid down in the Naulilaa Incident case.

After the creation of the United Nations, the principles of non-use of force and peaceful settlement of disputes have generally become a part of jus cogens, and therefore the use of force in reprisals has been prohibited (Article 2 para 4 of the Charter). Also, article 33 of the Geneva Convention forbids reprisals against persons protected therein.
Actions taken in reprisals are illegal and are taken exceptionally, by a State to obtain justice. In reprisals, a State takes law into its own hands.

Embargo:

The term Embargo is of Spanish origin. Ordinarily, it means detention, but in International Law, it has the technical meaning of detention of ships in port. Hyde defines embargo as the detention within the national domain of ships or other property otherwise likely to find their way to foreign territory. The embargo may be applied by a State in respect of its vessels or to the vessels of other States. When a state confines the operation of the embargo to its vessels, it is known as a civil or pacific embargo. Such an operation is initiated by an order issued by State authorities to limit or interrupt or terminate its trade and economic relations with another state. The purpose is to exert financial or economic pressure on the other state.

When ships of other states are detained which as committed a breach of an Internal Law, the embargo is said to be hostile. The purpose of such an embargo is to compel another state to settle the dispute. Such an embargo is a form of reprisals.

Embargo at present may be applied by a State, individually, or collectively, under the Authority of the United Nations. If an embargo is applied by a state, it should not endanger international peace and security. If it does so, it would become illegal. The collective embargo may be applied under the authority of the Security Council against a delinquent State.

Pacific Blockade:

When the coast of a state is blocked by another state to prevent ingress or egress of vessels of all nations by the use of warships and other means to exercise economic and political pressure on that State, the act is called blockade. When applied during peacetime, it is known as the pacific blockade. The essential requirements are that the blockade should be declared and notified; the blockade must be effective.

As to the validity of the pacific blockade, in international law, there was a difference of opinion among jurists, but after the creation of the United Nations, application of the pacific blockade has become illegal because it threatens peace and security.

Collective blockades, when applied under the authority of the Security Council are not illegal. It was applied against Iraq in 1990.

Intervention:

It is another compulsive means of settling disputes between states, short of war. According to Professor Oppenheim, it is the dictatorial interference by a State in the affairs of another State to maintain or alter the actual condition of things. Professor Winfield has classified intervention in three categories, i.e. Internal, External and Punitive Intervention.

Conclusion:
Peace cannot be established in the world unless states as separate entities from their citizens are not inclined to solve the disputes. As the magnitude of a dispute between the states is multiple times larger than that of the dispute between individuals, the result of its resolution is also multiple times larger than that of the resolution of a dispute between individuals. Hence, individual states must resolve to solve all the disputes, by using amicable means. This is inevitable for the peace of the world, when several complexities, both legal and factual, increase the number of disputes too.

Bibliography:

1. H.O Agrawal, International Law & Human Rights, (22nd ed.) Central Law Publication, Allahabad
2. Christian Tams, The settlement of International Dispute, University of Oxford
3. Malcolm N. Shaw, International Law, 5th Edition, Cambridge University Press