Utopianism at the point of a gun (or spear) is one of humanity’s oldest psychoses. From Victor Davis Hanson at nationalreview.com:

Utopianism is age-old, as are its tragic consequences — and we haven’t seen the worst yet.
Bouts of extreme leftism are frequent in history. Plato’s Apology, Edmund Burke’s Reflections on the Revolution in France, and Vladimir Lenin’s What Is to Be Done? — all offer us insight into the mind and methods of the hard Left.
America has experienced surges of mainstream anarchism, socialism, and communism, most profoundly during the late 19th century, amid the Great Depression, during the Soviet-American alliance of World War II and afterward, and in the 1960s. But rarely have these radical movements openly and without apologies made such inroads into and inside government and the establishment as during the past decade.