What is the basic theme of the poem "The Second Coming"?

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Key to understanding this poem is the way that
the poet uses irony to challenge our expectations. The title, "The Second Coming," leads
us to believe that this poem concerns the traditional belief of the Second Coming of
Jesus, a time of peace and justice for all humanity. However, the second coming of this
poem will, by contrast, be associated with a new era of warfare of savagery,
characterised in the following lines:

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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 poem ends with
an ominously ironic tone as the "rocking cradle" at Bethlehem in which Jesus the baby
was born is placed next to the arrival of a "rough beast" that seems to symbolise the
advent of the grim epoch that humanity will face in the
future.

Thus the poem points towards a horrendous future.
It is important to remember that this poem was written in the aftermath of World War I,
which was a historical event that shocked so many people. Thematically therefore, Yeats
uses this poem to express his distrust in the comforting belief of the Second Coming.
For Yeats, looking at history only reveals how, more and more, "the ceremony of
innocence is drowned" and mankind is characterised by darkness, warfare and violence, as
in the First World War. Looking ahead, Yeats sees no light at the end of the tunnel, but
an ever more marked collapse of society.