Alliances are arrangements between states and, in some cases, independent authorities other than states.

Alliances are explicit agreements. Nevertheless, explicitness of an alliance agreement does not necessarily mean that the agreement is made by a formal treaty and declared to other states and registered with the United Nations.

General commitments such as the League of Nations, the United Nations, or their affiliated specialized agencies and the Organization for Security and Cooperation in Europe (OSCE) are not considered formal military alliances.

The arrangements for mutual security and general defense cooperation like the US-Turkey Defense and Economic Cooperation, which deals exclusively with bases, military aid, financial aid, and training programs, are not considered as alliances (Krause
and Singer, 2001).

Alliances contribute to the national security of states. Alliances provide states an air of seriousness that clearly distinguishes them from agreements in other areas of foreign policy, such as finance or commerce.