Dan 4:32 And they shall drive thee from men, and thy dwelling shall be with the beasts of the field: they shall make thee to eat grass as oxen, and seven times shall pass over thee, until thou know that the most High ruleth in the kingdom of men, and giveth it to whomsoever he will.
No matter how powerful the nation or ruler, God is still God. Nebuchadnezzar was the ruler of the world empire, the most powerful man on earth. Yet God humbled him, made him become as an animal grazing in the fields to show him that God was the ruler over all the earth. No matter how powerful nations and rulers appear, they are still ultimately responsible to God. God still rules, God still ultimately determines the destiny of nations. Don’t fear, trust the future to God.