Because of its vague and sweeping language, the 14th Amendment gave the
courts great latitude in deciding what is due process and what is equal
protection under the law. For example, during the Lochner Era, the
Supreme Court believed that the private right of contract was protected
by the due process clause. That view of the due process clause has since
been discarded. Instead, the 14th Amendment was used to incorporate the
Bill of Rights, which meant that states could no longer abridge freedom
of speech, religion, procedural due process rights in the 5th
Amendment, etc. At this point, the only amendment that has not been
incorporated is the 2nd