Milton Friedman had a very elegant and impassioned argument against the draft.

"In the course of his [General Westmoreland's] testimony, he made the statement that he did not want to command an army of mercenaries. I [Milton Friedman] stopped him and said, 'General, would you rather command an army of slaves?' He drew himself up and said, 'I don't like to hear our patriotic draftees referred to as slaves.' I replied, 'I don't like to hear our patriotic volunteers referred to as mercenaries.' But I went on to say, 'If they are mercenaries, then I, sir, am a mercenary professor, and you, sir, are a mercenary general; we are served by mercenary physicians, we use a mercenary lawyer, and we get our meat from a mercenary butcher.' That was the last that we heard from the general about mercenaries."

Remember, this was the time when an all-volunteer Army was deliberately and incorrectly characterized as a mercenary force,

Rather than a draft, simply institute "the Heinlein option" -- those who wish to vote and holding public office have to serve the country in some capacity first, either in the military, or perhaps a longer term in civilian service. The difference between this an a draft is, a draft defines everyone as a citizen and then demands service, while this asks for service, and then grants citizenship to anyone who answers the call. No need for deferments or running off to Canada to escape the draft, and no aging chickenhawks sending other people's sons to war without having made a similar sacrifice.