The Catholic Church's teaching on war and peace is complex and multifaceted, rooted in the principles of justice, charity, and the pursuit of peace. It encompasses both the conditions under which war might be considered morally permissible (just war theory) and the active promotion of peace and non-violence.

The Call to Peace

The Church consistently emphasizes the paramount importance of peace. Peace is not merely the absence of war but is understood as "the tranquility of order," a fruit of justice and charity. It is seen as an essential good, reflecting God's own peace and the ultimate goal of human society. The Catechism of the Catholic Church states that "respect for and development of human life require peace".

Just War Theory

While strongly advocating for peace, the Church recognizes that in certain extreme circumstances, the use of force may be morally justifiable as a last resort to defend innocent life and uphold justice. This is articulated through the "just war theory," which has evolved over centuries, drawing from the writings of figures like St. Augustine and St. Thomas Aquinas. The Catechism of the Catholic Church outlines the strict conditions for legitimate defense by military force, which must be rigorously met :

• Damage Inflicted by the Aggressor Must Be Lasting, Grave, and Certain: The harm caused by the aggressor must be serious and undeniable.
• All Other Means of Putting an End to It Must Have Been Shown to Be Impracticable or Ineffective: War must be a last resort, undertaken only after all peaceful means of resolution have been exhausted.
• There Must Be Serious Prospects of Success: There must be a reasonable hope that the military action will achieve its just objectives and not lead to a worse outcome.
• The Use of Arms Must Not Produce Evils and Disorders Graver Than the Evil to Be Eliminated: The potential harm caused by the war itself must not outweigh the harm it seeks to prevent. This is known as the principle of proportionality.

These four conditions are cumulative, meaning all must be met for a war to be considered just. The Church also stresses that the decision to wage war belongs to the legitimate public authorities, who have the right and duty to impose on citizens the obligations necessary for national defense.

Conduct in War (Jus in Bello)

Even if a war is deemed just, there are moral limits on how it can be conducted. The Church teaches that:

• Non-combatant Immunity: Direct attacks on non-combatants, such as civilians, wounded soldiers, and prisoners, are strictly forbidden.
• Proportionality: The force used must be proportionate to the military objective, avoiding excessive destruction.
• No "Blind Obedience": Actions that violate international law or fundamental moral principles, such as genocide, are condemned. Blind obedience to orders that command such actions is not an excuse.

The Role of Conscience and Conscientious Objection

The Church upholds the right to conscientious objection, stating that "those who are sworn to serve their country in the armed forces are agents of security and freedom of nations. As long as they fulfill their duty in this way, they are true servants of peace". However, it also recognizes that "public authorities should make equitable provision for those who for reasons of conscience refuse to bear arms; these are nonetheless obliged to serve the human community in some other way".

Promoting Peace

Beyond the just war criteria, the Church actively promotes various means of achieving and maintaining peace:

• International Law and Institutions: The Church supports the development and enforcement of international law and the role of international organizations in resolving conflicts peacefully.
• Disarmament: The accumulation of arms is seen as a grave threat to peace, and the Church advocates for regulated, reciprocal, and verifiable disarmament.
• Addressing Root Causes of Conflict: The Church emphasizes the need to address the underlying causes of conflict, such as poverty, injustice, and human rights violations.
• Forgiveness and Reconciliation: True peace requires a spirit of forgiveness and reconciliation, especially after conflicts.

Conclusion

In summary, the Church's teaching on war and peace is a nuanced framework that prioritizes peace as a fundamental good, while acknowledging the tragic necessity of defensive force under extremely strict conditions. It calls for constant efforts to build a just and peaceful world, guided by charity and respect for human dignity.