Hugo Grotius discusses the just causes of going to war, especially the idea that the capacity to wage war must be matched by the intent to do so (1625)
Hugo Grotius attempted to codify the historical, moral, and legal grounds for justly waging war against an enemy. Here are his thoughts on waging war against a perceived threat:
War & Peace
First therefore, the Dread (as we before observed) of our Neighbour’s encreasing Strength, is not a warrantable Ground for making War upon him. To justify taking up Arms in our own Defence, there ought to be a Necessity for so doing, which there is not, unless we are sure, with a moral Certainty, that he has not only Forces sufficient, but a full Intention to injure us.