When I was draft-eligible eons ago, I got it into my head that compulsory selective service was unconstitutional because it was "involuntary servitude" as banned by the 13th Amendment. I hounded all my lawyer and law-student acquaintances about this, not realizing how specialized Constitutional law was. Some said the draft was legal because the Constitution gave Congress the power to raise and maintain standing armies. Others said the Constitution made the President Commander-in-Chief (which was why draft notices began with "greetings from the President of the United States"). Still others said that the intent of the framers of the 13th Amendment was to outlaw "negro slavery," not anything else.

I finally figured it out years later: the 14th Amendment's due process clause protected the draft. The Selective Service Act had a plethora of exemptions and deferments; subjected potential draftees to physical and mental exams, and provided a process to appeal your classification to various boards--and ultimately to the President. So much for "involuntary servitude."