Answer: Vietnamization was the policy to end the U.S. involvement in the Vietnam war.
Explanation:
War changed because the new policy made it where the U.S. troops involvement was going to end, and they were no longer going to partake in the Vietnam War
The North was generally "Free-Soil." This meant that they supported the idea of wage-labor versus slavery; also they opposed the spread of slavery into Western territories, The North was very industrial.
The South's economy was based on slavery. Southern men believed that it was essential to their liberty to maintain slaves. The South had very little industry and was almost entirely an agrarian region.
The Western Territories were fought over between the North and the South for influence (whether or not they could bring slaves with them as settlers. Look into Missouri Compromise," Nullification Crisis (when South Carolina attempted to secede from the Union)," "Compromise of 1850."
The issue that historians can gain insight from on this excerpt is the Southern Secession. In 1860 and 1861, eleven southern states declared they wanted to succeed.