Because, it was a huge war, with many deaths. It was a Major part of WWII. the invasion of Normandy France. There are books upon books that I could write to answer that question, but alas, I lack the proper time.
<span />
You might be talking about the Stanford v. Kentucky (1989),
where the U.S Supreme Court ruled that offenders at least 16 years old at the time
of the crime can be punished with death penalty. Doing so would not constitute
cruel and unusual punishment. That means 16-year olds who committed heinous
crimes can be put to death. The ruling was overturned with the Roper v. Simmons
in 2005, which forbade capital punishment for juveniles.
