**The debate around preventative war is highly complex, controversial, and relevant to the times we live in.** • [“Preventative war occurs when a state launches a military conflict to prevent another state or other international actor from becoming a threat”](https://www.encyclopedia.com/defense/energy-government-and-defense-magazines/preventive-war). Whilst war is a lot of the time the result of a particular crisis or event, preventative wars are a response to “a perception of a potential change in the future balance of power” between a state and its adversaries. The reason some argue against preventative war, is because prevention “can occur during times of relative peace” and consequently disrupt international order. Others insist the threat posed is sometimes too great to ignore. • Using the [Just War Doctrine](https://www.bbc.co.uk/ethics/war/just/introduction.shtml), preventative war can be justified so long as it satisfies the basic requirements for going to war such as necessity and proportionality. It attempts to deal with three principles - taking a human life is wrong, states must defend their citizens and protecting human life and morals can sometimes require the use of force and violence. Preventative war can arguably be ok in _some_ circumstances. • One of the most famous and controversial examples of preventative war, was during 2003, when the US led a coalition of war against Iraq on the grounds that Saddam Hussein’s regime was developing weapons of mass destruction. Many agreed with the decision to go to war in Iraq and cited it as a justifiable response to the threat posed. On the other side of the debate, many condemned the war. Regardless _“that debate is likely to continue for many years”_.