Something the Dog Said wrote: In regard to the involuntary servitude, why does the federal government have the authority to force individuals into military service against their will? Could the government simply institute a mandatory draft of all individuals and give the option of non-military service if desired? I believe that they allowed conscientious objectors that option.
Better question is why does the federal government believe it has the authority to force individuals into military service given that our Constitution forbids involuntary servitude? Before the adoption of the 13th Amendment it might have been permissible, but after that amendment was ratified that option was taken off the table. Might that make it difficult for the Congress to raise an army for the common defense of the union? Yeah, it might, but no exception to involuntary servitude was carved out of the law to allow Congress to force individuals into military service.
