An Alliance is a coalition of states that coordinates their actions to defend any military attack. It is the fourth element of the traditional security policy.

The advantages of forming an alliance are mentioned below:

a. Most alliances are formulized in written treaties and are based on a fairly clear identification of what constitutes the threats.

b. The countries form alliances to increase the effective power relative to another country or another Alliance.

c. It is based on national interest and can change when the national interest changes.