The Fourteenth Amendment to the United States Constitution is one of the post-Civil War amendments and includes the Due Process and Equal Protection Clauses. It was proposed on June 13, 1866, and ratified on July 28, 1868.

The amendment provides a broad definition of national citizenship, overturning a central holding of the Dred Scott case. It requires the states to provide equal protection under the law to all persons (not only to citizens) within their jurisdictions.

http://en.wikipedia.org/wiki/Fourteenth_Amendment_to_the_United_States_Constitution