The poem "Flag" explores nationalism and the power of symbols to unite or divide people. It questions why people feel such devotion to their nation's flag, which is ultimately just "a piece of cloth". Through its repetitive structure and contrasting language, the poem illustrates how flags can inspire people to fight and die for their country while also creating conflict between groups. In the end, the speaker acknowledges the flag's strong hold over people and their need to feel a sense of belonging, despite seeing nationalism as an abstract concept invented by mankind.