Pretty sure the 13th Amendment guarantees this, in theory. (Corporations aren't natural persons, but forcing a corporation to provide a service boils down to forcing people to provide a service.)
The Supreme Court has upheld the Selective Service Act as allowable under the 13th Amendment as something other than involuntary servitude, repeatedly since 1918. So personhood isn't much of an obstacle to conscription.
The Supreme Court has upheld the Selective Service Act as allowable under the 13th Amendment as something other than involuntary servitude, repeatedly since 1918. So personhood isn't much of an obstacle to conscription.