The correct answer to this open question is the following.
Unfortunately, you forgot to attach the excerpt of the text.
Where is it? What does it say? Without the text, we do not the content. Just you.
However, trying to help, we can comment on the following about the idea of U.S. territorial expansion.
The imperialistic or expansionists ideas of the United States are based on the concept known as the "Manifest Destiny."
Although the specific term "Manifested Destiny" was coined until 1845, it was used as a was y to allow the expansion of white American settlers into territories that belonged to the Native American Indian tribes. This expansionist idea dominated the 1900s and under the idea that God blessed the "white" people in the United States to expand and settle new territories, forcing the Indians to leave their lands.
The federal government created legislation that supported the settling of the whites.
Years later, and after the United States victory in the Spanish-American War. the US government took possession of the Philippines, Puerto Rico, and Guam.
Another example was the Mexican-American War, in which after the signing of the Treaty of Guadalupe-Hidalgo, the United States gained large portions of land that belonged to Mexico. We are talking about California, Nevada, Utah, Arizona, and parts of New Mexico, and Colorado.
