Why were the provisions of the 14th Amendment not included in the original Bill of Rights?

There are two main provisions of the 14th Amendment that are important today (Sections 2-5 were really only relevant at the time that the Amendment was ratified).  There are different reasons why each of these two provisions was not included in the original Bill of Rights.

The most famous provision of the 14th Amendment says that states cannot deny to anyone “the equal protection of the laws.” This provision was meant to ensure that the states would not make laws that would treat African Americans differently from whites.  This provision was not included in the Bill of Rights because essentially no one in the late 1700s believed that blacks should be legally equal to whites.  The people who wrote the Bill of Rights believed that whites were superior and they did not anticipate a time when people would believe otherwise.

The second important provision of the 14th Amendment says that states cannot “deprive any person of life, liberty, or property, without due process of law.”  This clause has been used to “incorporate” the Bill of Rights.  That is, it has been used to say that the Bill of Rights applies to the states as well so that state governments, for example, cannot make laws abridging the freedom of speech.  James Madison proposed similar provisions for the Bill of Rights, but these were rejected.  This was because people at that time believed that the state governments were not dangerous. They feared that the national government, which was not closely tied to people in the states, might take away their rights but they did not think that the state governments would do so. Therefore, they saw no need to include any language specifying that the Bill of Rights would apply to the states.