Why did states seek to resolve their international problems not through negotiations, but through war?

For a long time, the main way to resolve all interstate conflicts was the use of military force or the threat of its use. A state with a greater military power could dictate its terms to its weaker neighbor. This way of solving interstate contradictions was called the law of war. At the same time, the state that committed the attack and the state that was subjected to it were legally in an equal position. This allowed the stronger states to unleash wars even without a special foreign policy reason, that is, when there were no direct disagreements with neighboring countries. The internal political situation, the need to expand their borders or the desire to improve their economic situation were often sufficient grounds for starting hostilities. At the same time, any war, regardless of the reasons that caused it, was waged by similar methods and led to the same consequences: the death of people, the ruin of entire regions, and other innumerable disasters.