The Evolution of the American Invasion Narrative traces the development of the tradition of American invasion narratives from their explosion in popularity at the end of the nineteenth century to the present day. Beginning as verisimilitudinous puritanical jeremiads, American invasion narratives evolve through time to reflect America's historical and cultural context, expanding into science fiction metaphors to represent ideas and anxieties as constantly re-imagined invaders from outside the nation. Inspired by fear of invasion rather than actual invasion, the United States provides the perfect setting for these narratives. Having discounted the origin of the modem nation by European colonists as 'civilisation' rather than invasion, the United States is presented as an imaginative space free from significant historical precedent, amenable to any invader or type of invasion that a writer could conceive. The growth of the nation into an imperial and military superpower coupling economic and technological progress with an increasingly expansionist political agenda moved the nation towards new frontiers. This in turn encourages writers to create newer, deadlier invaders to be outwitted and outfought by the genius of the American scientific imagination and the determination of the American spirit of republican liberty. Invasion narratives help America to semantically reinvent its imperialism, encouraging expansion as a way of fortifying itself against the attacks presented in the fiction and also as benevolent to the rest of the world, a peaceful assimilation compared to the violent alternatives of other ideologies.