One of the key themes of modernism is the idea of the individual in a rapidly changing and fragmented world. ‘The Second Coming’ reflects this theme through its emphasis on the breakdown of traditional social and political structures. Yeats suggests that the world is in a state of chaos and anarchy, and that there is no longer any sense of order or control.

The poem's use of fragmented imagery also reflects the modernist style. Yeats uses a series of disjointed and sometimes surreal images to convey the sense of a world in flux. For example, he describes ‘a vast image out of Spiritus Mundi,’ which is a reference to a collective unconscious that is shared by all humanity. This image suggests that the world is interconnected in ways that are not immediately apparent, and that there are hidden forces at work that are beyond human comprehension.

The poem’s use of symbolism is also typical of modernist literature. Yeats uses a range of symbols, including the falcon, the Sphinx, and the ‘rough beast,’ to represent different aspects of the human experience. These symbols are open to interpretation, and they suggest that the world is complex and multifaceted.

Finally, the poem's style is also typical of modernist literature. Yeats uses a range of literary techniques, including alliteration, repetition, and parallelism, to create a sense of rhythm and movement. The poem's use of free verse also reflects the modernist style, as it allows Yeats to experiment with form and structure in new and innovative ways.

‘The Second Coming’ is a modernist poem because it reflects the themes, imagery, and style that are typical of modernist literature. It explores the individual’s place in a rapidly changing and fragmented world, and it uses a range of literary techniques to create a sense of complexity and ambiguity.