Answer:
It banned slavery in the territories acquired after the War with Mexico
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After the World War II and all of the terrors witnessed through it on ethnic and racial basis, the international community was determined that something like that should never happen again, and that all humans are equal and deserve the same rights.
That benefited the African American population in the United States a lot, as they now had the basis and support with which they were able to push through to gain all of the rights they deserve, thus be equal with all of the rest. That led to the formation of multiple organizations for the rights of the African Americans, widespread propaganda, protests, and eventually it gave a positive result, with the African Americans gaining all of the rights they deserved, but also putting the racism aside in the American society.
Lusitania was an important event in World War I. The death of so many innocent civilians at the hands of the Germans galvanized American support for entering the war, which eventually turned the tide in favor of the Allies. The Lusitania was a British luxury cruise ship.
