Final answer:
The Mexican-American War can be viewed today as an act of aggression by the United States due to its expansionist ambitions and negative consequences for Mexico.
Step-by-step explanation:
The Mexican-American War can be viewed today as an act of aggression by the United States. The war was primarily driven by U.S. expansionist ambitions, as evidenced by President Polk's actions and the acquisition of Mexican territories. The war also resulted in negative consequences for Mexico, including loss of land, displacement of Hispanic populations, and strained relations with Latin America. Therefore, option b) As an act of aggression by the United States is the most accurate viewpoint to take.