The US became a world power at the turn of the century string from when the British invaded Northern America.
Explanation:
When the Britishers invaded the Northern America the US got a chance to improve and expand. America also invaded all the land owned by the Native Americans. Also after taking the land from Mexico at another war. Which is still under disputes.
America chose to become a European style Imperial power. It did not stop till there but also stole Hawaii through colonialism. World war I and World war II destroyed Europe and Asia but could not destroy America. And therefore, US became superpower.