An adversary or foe is a person or group who is thought to be violently opposed or threatening. It has been noticed that the notion of an adversary is "fundamental for both people and groups." Adversaries can be real or perceived, but they must have the ability to harm your interest. Enemies are those who can do so intentionally. The word "adversary" comes from the Latin adversus, meaning "against". In law, an adversary is a party against whom a right is asserted or a duty is owed. A judge will usually not decide in favor of one party over another, but instead decides between the parties based on what he or she considers to be the most important issue in the case. Similarly, a jury determines the outcome of an action by weighing the evidence and coming to a conclusion on which side they believe will win at trial. In war, an adversary is someone who fights against you. This could be another country, but it often means people who fight under your own flag. During the American Civil War, the Union Army referred to the Confederates as its adversaries because they fought them directly rather than working within the system to improve their situation. Today, Americans use the term with respect to terrorists who threaten our way of life and seek to destroy us if we are successful.