Well, once the Americas were discovered and the colonist found that the soil was agreeable to grow different crops such as tobacco and cotton the colonists realized that they needed people to pick the crops. Originally indentured servants did the hard labor but then when they found that they could get labor by trading goods with African tribal leaders they resorted to importing Africans to the Americas as labor. The tribes in Africa were constantly fighting and whichever side won the losers became the slaves of the winning tribe. However, as Europeans brought valuable things to the continent of Africa such as weapons, salt, gold, and other things the leaders of the winning tribe would give their slaves to the Europeans. There were cases when Blacks captured other Blacks in Africa for the sole purpose of giving them to the European traders. Hopefully this helps. If you haven't see the movie La Amistad, it will explain in more detail what I have written. I learned a lot from that movie. I must warn you the first 5 to 10 minutes are a bit gory. I had a hard time watching that part.
Containment is a geopolitical strategic foreign policy pursued by the United States. It is loosely related to the term cordon sanitaire which was later used to describe the geopolitical containment of the Soviet Union in the 1940s. The strategy of "containment" is best known as a Cold War foreign policy of the United States and its allies to prevent the spread of communism after the end of World War II.
First to sing the Declaration of Independence