As I recall, it has been held that the "involuntary servitude" provision doesn't apply to the military draft because it is overruled by the Constitutional grant of power to Congress to "raise armies." I wonder about that logic, but, through some carelessness on the part of those in power, I'm not on the Supreme Court. Even if you accept that logic, though, it would seem to apply only to the military, not service for any other purpose.

Peter.