Another argument that could be put forward is that, violence only leads to more violence. An example of this is the effects of the war in Iraq which have led to guerrilla activities everyday such as car bombs even after Sadam Hussein was captured. Car bombs were even thrown on Red Cross’ transportation.
Also, the need for war would disappear if the money spent on weapons was spent instead on eradicating the causes of the war, for example, poverty.
A Christian pacifist could say that the aim of non-violent conflict is to convert your opponent; to win over their mind and heart and persuade them that your point of view is right. Also, Peace Pilgrim said that:
“Many people know the simple spiritual law that evil can only be overcome by good. Pacifists not only know it, they also attempt to live it.”
Additionally, Ralph Waldo Emerson said:
“Peace cannot be achieved through violence, it can only be attained through understanding.“
However, a theory was created by St. Thomas Augustine, developed by Thomas Aquinas around 1250CE and additionally developed by the Roman Catholic Church, which was called the “Just War” theory. The aim of this theory was to provide a guide to the right way for states to act in potential conflict situations. This gives criteria that need a legitimate authority, have a just aim and intention, be waged proportionately and with discrimination and have a good chance of success. Not just the aim of the war, but the means used to fight it must be in proportion. Therefore, only enough force and no more should be used. Consequently, retaliating with a nuclear weapon in would make that war unjust, even though the cause of the war may be just.
Many would argue that the Second World War was a “Just War” because it was in charge by a legitimate authority, it had a clear aim, to get rid of Hitler and his soldiers, it was waged proportionality as weapons of mass destruction were not used and there was a good chance of success.
Christian non-pacifists may support their position by arguing that in fact, Jesus used violence:
Early in the morning, as he was on his way back to the city, he was hungry. Seeing a fig-tree by the road, he went up to it but found nothing on it except leaves. Then he said to it, “May you never bear fruit again!” Immediately the tree withered.
(Matthew 21: 18-19)
Why can not we use violence, as, God used war as a way of enabling the Israelites to take possession of the Promised Land?
Also, they could argue that Jesus forbade personal violence and that his teachings referred to the Kingdom of God, not the real world in which we live.
Violence is sometimes necessary in order to protect the weak and enforce law and order in society. That is the reason why policemen carry with them batons and guns. For example, in a violent rebellion, police need to use violence and force against the perpetrators as otherwise innocent civilians may get hurt or killed.
Non-pacifists could additionally argue that if we are improving peoples’ lives, we are right to go to war. This is the message given by Isaiah:
“Is this not the king of fasting I have chosen: To loose the chains of injustice and untie the cords of the yoke, to set the oppressed free and to break every yoke?”
(Isaiah 58:6)
Also, most societies and people regard going to war as fulfilling a citizen's ethical duty, they honour and remember those who gave their lives in wars, for example, the Second World War.