The case for absolute opposition
Pacifism holds that organised killing is morally wrong even when undertaken for a claimed good. War predictably harms civilians, corrupts institutions and creates further cycles of violence.
The argument from self-defence
A state or population under attack may have a moral right to defend life, territory and political independence. Refusing all resistance could allow aggression, occupation or mass killing to continue.
A just cause is not enough
Even where defence is legitimate, methods still matter. Deliberate attacks on civilians, torture and indiscriminate force cannot be justified merely by appealing to an honourable objective.
Necessity and proportionality
Force should be used only when non-violent alternatives are inadequate and when the expected harm is proportionate to the threat being prevented.
Uncertainty weakens justification
Governments often act upon incomplete intelligence, propaganda and exaggerated threats. Moral confidence should therefore be lower than political leaders commonly suggest.
War may be the least harmful option
In extreme cases, limited force may prevent greater violence. This does not make war good; it means that every available choice may involve serious harm.
Evidence notes
Assessment should examine the immediacy of the threat, exhaustion of peaceful alternatives, proportionality, civilian protection, realistic objectives and whether the decision-makers have presented reliable evidence.
Ethical questions
Can defensive war remain morally justified when civilians will foreseeably die?
Who decides when peaceful alternatives have genuinely failed?
Does a just cause excuse unjust methods?
Conclusion
War may sometimes be morally defensible as a last resort against grave aggression, but it is never morally simple. A justified cause does not remove duties of restraint, civilian protection, honesty and accountability.