World leaders are fighting because they have no unity. That is because of what 1 John 5:19 says: "We know that we originate with God, but the whole world is lying in the power of the wicked one." Satan has power over the world, then he influences humans to be as selfish, greedy, and shortsighted as he is. Consider also what Jeremiah 10:23 says about man - I well know, O Jehovah, that man’s way does not belong to him. It does not belong to man who is walking even to direct his step." God did not create humans to live independently of his rulership and be successful. In a vain attempt to be independent of God’s rule, humans have set up different political, economic, and religious systems. These differences have brought people into constant conflict with one another, resulting in violence, war, and death.
Shortly, God will intervene in human affairs to assert his rulership over the earth. Bible prophecy states: “In the days of those kings [human rulerships now existing] the God of heaven will set up a kingdom [in heaven] that will never be brought to ruin. And the kingdom itself will not be passed on to any other people [never again will humans rule the earth]. It will crush and put an end to all these [present-day] kingdoms, and it itself will stand to times indefinite.”—Daniel 2:44.