On Wed, 16 Mar 2016 12:39:23 -0400, Keyser Söze
wrote:

There is nothing in the Constitution that
requires military or any other form of government service or duty, and
therefore there is no requirement, period.

There are plenty of social "obligations" that are not defined in the
constitution. It would have been easy for me to dodge the draft by
hiding in school. I had signed an "intent" letter with the CG when I
was 17 but those are really not binding.
It could be that I took JFKs words to heart "ask what you can do for
your country".