Answer:
In the 1800s, many Americans believed in the policy of Manifest Destiny. This meant that the nation’s mission was to expand to the Pacific Ocean.
Step-by-step explanation:
Manifest Destiny was an ideology according to which the American nation had for divine mission the expansion of "civilization" towards the West, reaching the Pacific Ocean.
It was defended by Republican Democrats in the United States in the 1840s, most notably by the "hawks" under the presidency of James Polk.
The phrase Manifest Destiny first appeared in 1845 in an article by New York journalist John O'Sullivan, published in the United States Magazine and Democratic Review, in which he urged the United States to annex the Republic of Texas. O'Sullivan used this expression to describe the "divine right" character of the irreversible colonization of the North American continent by the Anglo-Saxons of the East Coast.