| Term | Definition |
| Private International Law | Law pertaining to routinized transnational intercourse between or among states as well as nonstate actors. |
| Public International Law | Law pertaining to government-to-government realtions. |
| Good Offices | A third party offers a location for discussions among disputants but does not participate in the actual negotiations. |
| Conciliation | a third party assists both sides but does not offer any solution. |
| Mediation | A third party proposes a nonbinding solution to a conflict between states. |
| Arbitration | A third party gives a binding decision through an ad hoc forum. |
| Adjudication | A third party gives a binding decision through a standing court. |
| Nonintervention | The legal principle prohibiting one state from interferring in another state's internal affairs. |
| Just Cause | The state contemplating the use of military force must have a morally good objective. (Jus Ad Bellum) |
| Right Intention | War must be waged for the purpose of correcting a wrong and establishing peace and justice, not for revenge or some other malicious reason. (Jus Ad Bellum) |
| Last Resort | War should not be undertaken until all other reasonable means of resolving the conflict have been exhausted. (Jus Ad Bellum) |
| Poltical Proportionality | the harm caused by the fighting must not outweigh the good toward which the war aims. (Jus Ad Bellum) |
| Declaration By a Legitimate Authority | Duly constituted rulers must publicly declare a state of war. (Jus Ad Bellum) |
| Reasonable Chance of Success | States must not engage in futile uses of force. (Jus Ad Bellum) |
| Discrimination | Noncombatants must be immune from attack; civilians not engaged in their state's war efforts cannot be targeted. (Jus In Bello) |
| Military Proportionality | Combatants must cause no more destruction than is required to achieve their military objectives. (Jus In Bello) |
| Jus Ad Bellum | The justice of war. |
| Jus In Bello | The justice in war. |
| Reprisal | A hostile but legal retaliatory act aimed at punishing another state's prior illegal actions. |
| Military Necessity | A legal doctrine asserting that a violation of the rules fo war may be excused during periods of extreme emergency. |
| War Crimes | Acts performed during war that the international community defines as illegal, such as atrocities committed against enemy civilians and prisoners of war. |
| Collective Security | A security regime guided by the principle that an act of aggression by any state will be met with a unified response from the rest. |
| Preventive Diplomacy | Actions taken in advance of a predictable crisis to prevent superpower involvement and limit violence. |
| Peacemaking | Peaceful settlement processes such as good offices, conciliation, and mediation, designed to resolve the issues that led to armed conflict. |
| Peace Building | Postconflict actions, predominantly diplomatic and economic, that strengthen and rebuild governmental infrastructure and institutions in order to avoid recourse to armed conflict. |
| World Federalism | A reform movement proposing to combine sovereign states into a single unified federal state. |
| Political Intergration | The processes and activities by which the populations of two or more states transfer their loyalties to a merged political and economic unit. |
| Functionalism | A theory of political integration based on the asumption that technical cooperation among different nationalities in economic and social fields will build communities that transcend sovereign state. |
| Spill Over | The propensity for successful integration across one area of cooperation between states to propel further integration in other areas. |
| Neofunctionalism | A revised functionalist theory asserting that the IGOs states create to manage common problems provide benefits that exert pressures for further political integration. |
| Devolution | Granting political power to ethnopolitical groups within a state under the expectation that greater autonomy for them i particular regions will curtail their quest for independence. |