Answer:
Because fort Sumter allowed the confederates to create a valuable hole in the union
Explanation:
They pushed for a war against Britain to restore national honor. They insisted that invading British-held Canada would deprive the Native Americans of their main source of arms and drive the British out of Native Americans. They also believed that the British would make naval acknowledgement to get Canada back from the Americans.
The political boundaries of the U.S changed from 1845 to 1853 by increasing the territory and getting land as far out as California because the Americans fought the Mexican American war (1846-1848) that resulted in Mexico yielding the area we know as the Mexican cession have a nice day (: