The 14th Amendment also includes the Incorporation theory. This requires the states to grant its citizens the same rights as are listed in Constitution.

If memory serves, prior to Brown v. Board of Education the various State governments did whatever they so chose to do. States had this so called "police power" allowing them to make any laws that promoted for the health, safety, welfare, and morals of their people.

The Supreme Court included this incorporation theory in their verdice in the Brown v. Board of Education. This required state legislatures to uphold the rights guaranteed in the federal constitution.