Well, it is as always an interpretation.
There is this from the main Constitution, Section 8.
"To raise and support Armies, but no Appropriation of Money to that Use shall be for a longer Term than two Years;"
The Constitution does give the right to "support Armies".
But this & other authorities of government are not unlimited.
Even fans of the draft would agree that "support" cannot....
- Impose a religion upon soldiers.
- Enslave soldiers.
- Eliminate freedom of speech & assembly.
- Impose self incrimination.
Those limits are based upon original
and subsequent
amendments to the Constitution.
Government still has the right to raise & support
armies by purchasing materiel & services from
those willing to provide them.
How you weigh that in regards to the 13th, is a matter of interpretation. And you can have yours and I will have mine.
Evolution is subject to various interpretations.
But some are cromulent, & others are specious.
It all depends upon premises & reasoning.
The law is slipperier than science, but cogent
reasoning should still apply.
The draft is involuntary.
It is servitude.
The 13th Amendment unequivocally prohibits this.
The singular exception is punishment for a crime.
By what reasoning could you argue otherwise?