Just War thinkers, such as Hugo Grotius, resisted using fears about the enemy's intentions as grounds for preemptive military action. This conservative rendering of what was permissible came under pressure in debates about the military responses to Iraq, Iran, and other nations seeking weapons. Those arguing for a more permissive category of preventive war maintain that a prudent leader must anticipate developing military threats and respond before an act of aggression is imminent. Though the just war tradition must respond to the changing nature of military threats, if the tradition is to remain viable as a moral framework, it is vital that it not be made more malleabie in this area.
Clough, David, and Brian Stiltner. "On the Importance of a Drawn Sword: Christian Thinking about Preemptive War--And Its Modern Outworking." Journal of The Society of Christian Ethics 27.2 (2007): 253-271.