This is why the price of freedom is eternal vigilance.
From a horrifying little work by RJ Rummel (don’t read this before bed):
The one factor present in all this Chinese democide, and that in the Soviet Union, Nazi Germany, and other such cases of genocide, is arbitrary power….
Power kills. And absolute power kills en masse. Consider–the Soviet Union, 61,911,000 people murdered; the Chinese communists, 38,000,000; the Nazis, 17,000,000; the Chinese Nationalists, 10,214,000; the Japanese militarists in World War II, 5,890,000; the Khmer Rouge of Cambodia, 2,000,000; West Pakistan over East Pakistan, 2,000,000; Turkey during and after World War I, 1,500,000; and Yugoslavia after World War II, 1,105,000.