

This was the case with the Soviet Union and its Eastern Bloc after World War II. In more extreme cases, a country within the "sphere of influence" of another may become a subsidiary of that state and serve in effect as a satellite state or de facto colony. High levels of exclusivity have historically been associated with higher levels of conflict. Similarly, a formal alliance does not necessarily mean that one country lies within another's sphere of influence.

While there may be a formal alliance or other treaty obligations between the influenced and influencer, such formal arrangements are not necessary and the influence can often be more of an example of soft power. In the field of international relations, a sphere of influence ( SOI) is a spatial region or concept division over which a state or organization has a level of cultural, economic, military, or political exclusivity. A 1912 newspaper cartoon highlighting the United States' influence in Latin America following the Monroe Doctrine.
