If such a situation arises as mentioned above then in order to protect my country and its citizens from invaders, I may have to adopt violent means like war if the invader makes sudden attacks using weapons and artilleries. But, if the invaders does not use any weapon and tries to invade it shrewdly then I would also have to adopt shrewd and cunning methods in order to win over the invaders. Such answers are hypothetical and fully depends on the situation whenever it occurs.