Causes of War in Latin America Explained: Definitions, History, and Future
By Marcus Vance
The concept of a formal cause for war traces back to the Roman College of Fetials, a priestly body tasked with advising the Senate on whether a foreign entity had committed a violation worthy of military retaliation. If an adversary broke a treaty, violated diplomatic immunity, or raided Roman farmland, the priests would perform a formal ritual. Without an explicit, identifiable grievance, the campaign was deemed legally and spiritually illicit.
Over centuries, this ancient protocol evolved into the broader Western tradition of the just war doctrine (bellum iustum). Thinkers like Saint Augustine, Thomas Aquinas, and later Hugo Grotius codified two complementary branches of military ethics: jus ad bellum (the right conditions for initiating war) and jus in bello (acceptable conduct while waging it). Within this architecture, a casus belli serves as the factual anchor of jus ad bellum. It provides the public, formal explanation an authority presents to convince domestic populations and foreign rivals that armed force is an unavoidable act of defense rather than lawless piracy.
Modern jurisprudence strictly limits what actions qualify as a legitimate legal justification. Under Article 2(4) of the United Nations Charter, states must refrain from the threat or use of force against the territorial integrity or political independence of any state. The sole universal exception, outside of a UN Security Council resolution under Chapter VII, is individual or collective self-defense in response to an armed attack, detailed under Article 51. What Romans accepted as an insult to imperial honor would today constitute an unlawful act of aggression under the International Criminal Court’s 2010 Kampala amendments.
Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.
