American imperialism
In the late 1800s, the US supported American sugar planters who overthrew the Hawaiian monarchy, and by 1900 Hawaii became a US territory.
In 1898, Puerto Rico came under US control after the Spanish-American War.
The Philippine-American War occurred between 1899 and 1902.
President Theodore Roosevelt signed a treaty in 1903 giving the US permanent rights to the Panama Canal zone.
All of these represent moves by the United States to stretch its control and influence through a wider section of the world.