by John Marshall Harlan, Pollock v. Farmers' Loan Trust Company…
“ While property, and the gains, profits, and income derived from property, belonging to private corporations and individuals, are subjects of taxation for the purpose of paying the debts and providing for the common defense and the general welfare of the United States, the instrumentalities employed by the states in execution of their powers are not subjects of taxation by the general government, any more than the instrumentalities of the United States are the subjects of taxation by the states ”
