Jermaine Thomas was born on a U.S. military base in Germany to a naturalized U.S. citizen father and a foreign national mother. Thomas' father had not been physically present in the United States prior to his birth for a sufficient period of time to transmit citizenship to him. When Thomas placed in removal proceedings for criminal activity, he claimed to have been born in the United States by virtue of his birth on a military base, and thus, to be entitled to birthright citizenship under the Fourteenth Amendment. The Fifth Circuit disagreed, finding that birthright citizenship does not extend to military bases outside the territorial boundaries of the United States.
The full text of Thomas v. Lynch can be found here: http://www.ca5.uscourts.gov/opinions/pub/14/14-60297-CV0.pdf