Roper v. Simmons
Until 1988, the Supreme Court had put no limits on how old a person had to be in order to be executed.  This meant each state could set their own rules.  In some states, the minimum age for execution was as low as 14.  For example, in 1944, South Carolina executed a 14-year-old boy named George Stinney in the electric chair.  Stinney was the youngest person in the United States to be convicted and executed during the 20th century.