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Religious Studies

Just War theory


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Conditions for a Just War

A Just War is one which has to be fought but is conducted according to certain conditions. These were developed by Thomas Aquinas (c1225-74) and Francisco de Vitoria (c1483-1546) and are still referred to by Christians today.

The theory is not intended to justify all wars but to prevent them by showing that going to war - except in certain limited circumstances - is wrong. The intention was to motivate states to find other ways of resolving conflicts, prevent war and to limit its effects.

The conditions of a Just War are:

  • it must be fought by a legal recognised authority, eg, a government
  • the cause of the war must be just
  • the war must be fought with the intention to establish good or correct evil
  • there must be a reasonable chance of success
  • the war must be the last resort (after all diplomatic negotiations have been tried and failed)
  • only sufficient force must be used and civilians must not be involved

Some wars can appear to meet all of these conditions. For example, World War Two (1939-1945) would appear to have been a Just War:

  • it was fought by Germany and the Allied countries who were legal authorities
  • Germany was being attacked for invading other countries
  • the intention was to correct the evil Hitler was doing for Nazi Germany
  • the Allies felt that they had a reasonable chance of success and they did win
  • all forms of negotiation with Hitler and the Third Reich had failed
  • most of the fighting was limited to the armies concerned and to harbours and munitions sites

This looks as though it was a ‘properly constituted’ Just War, but actions like the Allied bombing of Dresden, a two-day raid by almost 2,400 bombers that destroyed the city and killed perhaps 135,000 civilians to virtually no military purpose, certainly broke the final condition.


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