There have been lots of cultures and civilizations that no longer exist. The ancient Greeks. The ancient Romans. The Assyrians, Babylonians, and Persians. The Egyptians and Kushites. The Ottoman, Mongol, and Maurya Empires. The Aztecs and Incas.
What happened to them? Some were defeated by other military powers, though other kinds of weakness often led to those defeats. Some of them fell due to what some historians call “social cannibalism.” That is, they turned against themselves. That is, they committed cultural suicide.
Victor Davis Hanson, who is not only a popular columnist but a professor of ancient history, fears something like that is happening to American culture and American civilization today. (Note: “Culture” refers to the organic values and customs of the people. “Civilization” refers to the accomplishments–the art, ideas, inventions, and government–of the culture.)