One thing it is too easy to do is to polarize people as dove’s or hawk’s. As people who want war or peace.
Few men are really going to be always for one or the other. The most ardent hawk will not want a war that he can’t win, and few doves will want peace if it would cost them the lives of everyone they know and love.
One exercise is to ask yourself what would cause your character to cross that line? What would cause your man of peace to go to war, or what would cause your man of war to sue for peace?
One thing I think Star Trek did well is show men of peace who are willing to go to war. Spock hates war, and would do his best to council against it or stop it, but there would be times and places it would be the only option and he would lead the charge. For example when it becomes clear who the Romulans are, vulcan’s who never embraced logic and who left home long before, he says war is the only way.
Kirk is more warlike for sure, and walks to the line more often then Spock does. But even so he never likes it, he sees force as a last resort, but nonetheless it IS a resort.