Your answer would be the printing press
Slavery occurred throughout the continent from the period of British colonization, in 1788-1868. specific groups of people including convicts, indigenous Australians and people transported from Asia and the pacific islands were made to labor in conditions which were either unpaid or under unilateral indenture contracts which were commonly not fulfilled.
With magic and people build an empire by breaking their peace and doing wars so there can be more land
Truman was the one who adopted a policy of containment. This (arguably) aggressive approach was what influenced America to get into wars such as the Korean War and other smaller conflicts. Meanwhile, Eisenhower was a bit less aggressive. Although his Secretary of State Dulles preached Brinksmanship and was very anti-Soviet, Eisenhower himself was somewhat against this, as shown when he did nothing to prevent the Hungarian Revolt. He also sought to increase U.S-Soviet Relations in the Spirit of Geneva, but the U-2 Incident pretty much erased most of his progress.