A coalition is combination of political parties to run a country's government. The British used this system of government during World War I and World War II. Coalition governments are usually found in countries where many political parties exist, and a single party rarely wins the majority.
The term "coalition" also may refer to an alliance of several nations against other countries. Often, such coalitions are formed directly before or during the course of a war. The coalitions formed before World War I greatly magnified an event that should have been handled internally and quietly. Coalitions were also formed during the reign of Louis XIV and during the Napoleonic wars.