The document to which this question refers is the justification for the Mexican-American War.
Answer:
The document shows how it was America's duty and responsibility for Americans to dominate and spread across the territories from the Atlantic to the Pacific.
Step-by-step explanation:
Manifest Destiny claimed that the USA had received from God the duty and responsibility to dominate the territories that stretched from west to pacific, in which case, dominating Mexico was a way of fulfilling the divine destiny that had fallen on the country, making with America to dominate a territory large enough to give it more power and influence to dominate the next territories.