The military gets to first attempt to fill their required slots. If any slots go wanting at the end of a 6 months cycle. Then those slots are fill by the closest degree to MOS match that can be made.
The draft pool would consist of the following stages. Stage 1 would be those college graduates who received Government grants. Stage two would be those college graduates who received interest free student loans. Stage three would be those college graduates who received government backed loans. Stage four would be those otherwise receiving government aid (well fare, subsidized housing, etc), and then Stage five the Selective Service registration. Lastly Stage six would be the general population.
However, draft should be limited to four years for non-combat, highly skilled positions and two years for combat positions (Active duty). The remaining balance of eight years to be served in Reserve/National Guard or civil service positions.
If enough people are not willing to stand up and defend it, then what's the point?