Just war theory holds that war can be morally justified only under strict conditions, whereas pacifism rejects war as a morally acceptable response to conflict. Within Christianity, these approaches reflect different interpretations of Jesus’s teachings, the duty to protect others and the authority of the state.
How Just War Theory Works
Christian just war thinking developed through writers such as Augustine and Thomas Aquinas. It attempts to reconcile love of neighbour with the responsibility to defend people against serious injustice.
It distinguishes jus ad bellum, the conditions for entering war, from jus in bello, the rules governing conduct during war. Common criteria include:
- Just cause: responding to serious aggression or protecting people from grave harm.
- Legitimate authority: war must be authorized by a properly constituted public authority.
- Right intention: the aim must be a just peace, not revenge or conquest.
- Last resort: reasonable peaceful alternatives must have been exhausted.
- Proportionality: anticipated harm must not outweigh the good sought, and force used must be proportionate.
- Reasonable prospect of success: war must have a realistic chance of achieving its just aims.
- Discrimination: combatants must distinguish military targets from civilians, who must not be deliberately attacked.
How It Differs from Pacifism
| Issue | Just war theory | Christian pacifism | | --- | --- | | Use of force | Permitted only when strict moral conditions are met | War is rejected; nonviolent responses are emphasized | | Protecting others | Armed defence may protect vulnerable people | Protection should involve nonviolent resistance, reconciliation and aid | | Christian examples | Roman Catholic teaching accepts conditional armed defence | Historic peace churches, including Mennonites, emphasize enemy-love and nonviolence |
The misconception that pacifism means doing nothing is incorrect. Pacifists may actively resist injustice without warfare. Neither position represents every Christian.
IB Exam Application
For Christianity’s Ethics and moral conduct theme, explain the belief-to-behaviour link. In a “Discuss” response, apply both approaches to a specific contemporary conflict, contextualize denominational examples and weigh protection of life against the harms of violence.