Racism has long been a pressing issue, particularly in America, but few people really consider the origins of the extreme racial tensions in America, buried back in early colonial times. Portentous indeed was that Dutch ship that brought the first batch of African slaves to the shores of Jamestown, Virginia in 1619.
There is a great deal of speculation about what caused the colonists to so readily accept slavery as a way of life. In Europe, there was distinct precedent for keeping servants, and many of the colonists who came as indentured servants were little better than slaves until they had worked their time, so the concept of keeping slaves was not as unseemly to them as it is to us today. A key difference, however, between the poor and indentured whites and the black slaves is that the whites had a set amount of time that they had to work, whereas the blacks were servants for life. Additionally, court records from the time period tend to show that blacks were given harsher punishments for equivalent crimes, indicating that the concept of racial inequality had already infested the minds of the populace. Some have speculated that, without having had fair exposure to African peoples, the white colonists used their physical differences as a convenient excuse to justify using blacks as slave labor. That is, without any preconceptions, a desperate need for low-cost workers was enough to instill a stereotype by which the ends could justify the means.
Blacks were not the only minority that was discriminated against in colonial America; native americans and indentured whites were also looked down upon by the mainstream. It was a popular fear that two of these groups would unite and rebel against their oppressors, a fear which culminated with Bacon's rebellion. As a result, the severity of the oppression increased. Indentured whites were not allowed to fraternize with blacks, interracial marriages were forbidden, punishments increased in severity for both races, and virtually no steps were taken to ensure the basic rights of the servants, regardless of race or age. Additionally, the governing bodies took steps to keep the native americans from interacting with african slaves any more than could be avoided. In 1738, Governor Lyttletown of South Carolina wrote that "it has allways (sic) been the policy of this government to create an aversion in them Indians to Negroes."
The discrimination against native americans also seems to have been largely a matter of convenience to the colonists. For a while, the colonists did not display any kind of racist attitude towards the natives of the continent. However, when they started to desire the land on which the native americans lived, the colonists began to justify their attacks with racially and culturally biased rhetoric, showing the first glimmers of Yanqui Imperialism (called "manifest destiny" by most politically correct textbooks). Additionally, the Virginian colonists seemed to resent the way that the natives were so easily able to live off of the land while the colonists starved through the cold winters.
These convenient hatreds perpetuated themselves through the following centuries. Hatred of native americans waxed as the caucasian population began to boom, and waned after they had seized all but a few small parts of the land. Since the desire for cheap labor persisted, so too did the accompanying discrimination of blacks. Even after the slaves were emancipated, racism persisted for two reasons: First, resentment lingered in those states which relied heavily upon slave labor, passed faithfully from parent to child; secondly, the African-American population persisted as a threat to the prosperity of low- and middle-class whites, particularly in the form of competition for jobs and education. Through the actions of such men as Dr. King, the country has made great steps towards dispelling the racist tendencies that continue to linger, but the issue of affirmative action shows that we still have a ways to go.
Sources:
Zinn, Howard. A People's History of the United States
http://www.socialistworker.org/2002-2/431/431_08_Racism.shtml
http://earlyamerica.com/review/2001_summer_fall/fugative~.html