By The Great Courses Staff

The United States has been accused of staging a coup to overthrow the Venezuelan government. Venezuelan President Nicolas Maduro warned that his country could become the next Vietnam War. Vietnam is still America’s least popular war. Maduro’s comments raise the question: Is war ever morally justified?

Leaders have always sought to justify war. War takes adults from their families. It costs taxpayers money and uses the nation’s resources. Most important, people die. How do we tell ourselves and our children it’s all worth it? Philosophers and theologians have asked this question throughout human history. Fortunately, an answer came in the form of the Just War Theory. Let’s study its three components.

The Just Recourse to War

When St. Augustine studied the Western Roman Empire, he found a huge paradox. The Empire was a state that encouraged peace, but its enemies often seized it. Because of this, Augustine reconciled that the Romans could be pacifists individually, but must be prepared with a recourse of war. Jus ad bellum is the Latin name for the Just Recourse to War. Augustine wrote, “It is the wrongdoing of the opposing party which compels the wise man to wage just wars.” For instance, we must only wage war for a just cause such as defending the innocent.

Thomas Aquinas also contributed to the Just Recourse to War. In fact, he added that a ruler must have just intentions for war, not merely a just rationality. Therefore, sincerity is key and justifications cannot ring hollow. “Augustine and Aquinas were not naive idealists,” said Andrew R. Wilson, Ph.D., Professor of Strategy and Policy at the United States Naval War College in Newport, Rhode Island. “But they did strive to create standards of justice in war based on the Judeo-Christian tradition.”

As Dr. Wilson points out, several other criteria apply. For example, only proper authorities should wage war and they should do so as a last resort.

The Just Conduct of War

By the 17th century, the Just Recourse to War had spread throughout the Western world. Around this time, a Dutch jurist named Hugo Grotius took steps to implement Just War Theory into law. Grotius introduced the concept of Just Conduct of War, or jus in bello. Just Conduct of War argues for ethical military practice. For example, countries should minimize civilian deaths and only target proven enemy military units. They should also refrain from using means that are “evil in and of themselves,” Dr. Wilson said. “This includes rape, torture, recruiting children,” and more.

“Abiding by jus in bello becomes all the more complicated when the adversary does not abide by the same norms,” Dr. Wilson said. “Counterinsurgency operations in Iraq and Afghanistan confront movements that intentionally blur the distinctions between combatants and non-combatants.” However, this tactic is also centuries-old.

The Just Termination of War

Recently, scholar Brian Orend proposed the third component of Just War Theory. “Jus post bellum concerns justice after a war, including peace treaties, reconstruction, war crimes trials, and reparations,” Dr. Wilson said. This component translates to Just Termination of War. In other words, there are qualifications to win a war justly.

Since Just Termination of War is a new term, it has more loosely defined qualities. Roughly, they involve dispensing fair treatment to the defeated nation. Peace treaties must differentiate between military and civilians. The winning side of the war must make reasonable demands of the losing side. Additionally, “fair and public trials are held for the senior leaders who violated jus ad bellum, and for the senior military commanders who violated jus in bello,” Dr. Wilson said. In other words, war crimes must be fairly addressed and punished in a court of law.

Few people truly want war because of its great costs. We learn in childhood that harming others is wrong. In addition, some wars seem as though they’re none of our business, like Vietnam. Several legal weapons of war truly devastate our opponents–for example, mustard gas and nuclear weapons. Just War Theory may or may not fall in line with our individual beliefs, but it is based on hundreds of years of research by great philosophers, theologians, and leaders around the world. In essence, it clarifies the best course of action for a worst-case scenario.

Dr. Andrew R. Wilson contributed to this article. Dr. Wilson is Professor of Strategy and Policy at the United States Naval War College in Newport, RI.