Postal Conscription
In the future, eighteen year olds will register for the USPS draft. If their number is drawn, they have to report for basic letter-carrier training.
One tour of duty is two years in low crime areas and one year in high crime areas.
You can enlist if you want.
If you are physically unable to be a letter-carrier, you can apply to work inside a post office.
Conscripts might flee to Canada to avoid their duties.