The great Irish poet William Butler Yeats (1865-1939).
Yeats wrote The Second Coming just after the Great War, in 1919:
Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;
The best lack all conviction, while the worst
Are full of passionate intensity.
The poem ends with:
And what rough beast, its hour come round at last,
Slouches towards Bethlehem to be born?
To Blawgletter, the scorchingest part of Yeats’s white hot words comes at the last of the first stanza: "The best lack all conviction, while the worst/Are full of passionate intensity." Damn scary, that.