Why was the Mexican war a turning point in history of AZ and us?

- The annexation of the U.S. Southwest brought a vast new territory known as "The Gadsden Purchase," under the American flag, including present-day southern Arizona

USA

- Acquisition of significant territorial gains, especially California and the present-day Southwestern United States (which led to the US Civil War)

- Increased tensions between pro-slavery and anti-slavery forces led to secession of Southern states

- Triggered a re-assertion of the federal government's dominance. This was significant not only regarding national issues within the U.S., but also to foreign actors and the global arena as U.S. began projecting global presence