What Is a War of Aggression?

For as far back as we have recorded history, wars have been waged in order for territorial gain or in order to conquer another nation. The concept that the stronger nation should prevail was largely accepted throughout the world until the 20th century, when the concept of aggression without justification began to lose favor. A new term — "war of aggression" — began to make its way into the nomenclature of many languages as a way to describe a war that serves no justifiable purpose, such as self-defense. Since then, the world view on aggression has changed to the point that crimes of aggression are now considered international crimes right along with human trafficking and genocide.

When one nation, or a faction thereof, engages in armed conflict against another nation without provocation, it is said to have waged a war of aggression. In modern times, a war of aggression is considered unacceptable among most nations of the world. Although the precise definition of a war of aggression may be disputed, most scholars agree that a war without the justification of self-defense fits the definition.

In most cases, a war of aggression is waged in order to gain territory or to subjugate the people of another nation. The war waged by the Nazis in Germany during the 1940s is generally considered to be a prime example of a war of aggression. A more recent example is the infiltration of Kuwait by Iraq in 1990, which ultimately led to the Gulf War.

The lack of a uniform definition for a crime of aggression or a war of aggression has been the main obstacle in prosecuting crimes of aggression on an international level. Although an International Criminal Court exists, its jurisdiction is limited and complicated. The Rome Statute of the Criminal Court, which is the international treaty establishing the court, does assert that crimes of aggression are punishable by the court; however, a uniformly accepted definition of aggression continues to be an issue among the member nations. In addition, not all nations have signed or ratified the treaty — among the notable absences are the United States, China, and India.

Until a uniform definition for crimes of aggression can be agreed upon, prosecution will remain elusive. Public opinion, however, and international consensus will be a deterrent to nations that may consider waging war on another nation without just cause. The United Nations, as well as numerous international treaties, will continue to serve as the authority on guidance regarding armed conflict until the International Criminal Court, or a similar body, is finally ready to fulfill that role.