Answer:
The Mexican-American War, waged between the United States and Mexico from 1846 to 1848, helped to fulfill America's "manifest destiny" to expand its territory across the entire North American continent.
Explanation:
https://www.history.com/topics/mexican-american-war
Northerners claimed the law was unfair. The flagrant violation of the Fugitive Slave Law set the scene for the tempest that emerged later in the decade. But for now, Americans hoped against hope that the fragile peace would prevail.
Oligarchy is the political system that is run by a group of noble families or wealthy members of a society. The term Oligarchy was first used by the great Aristotle for describing the powers that were held by a very small and highly privileged group. These people often misused their powers and treated the people under their rule very poorly and also used them to satisfy their selfish needs. It has been commonly seen that the rulers that believed in Oligarchy actually selected people on herediterary basis and not based on merit.