James Clark McReynolds,
Helvering v. Therrell — Opinion of the Court
“ No state may tax appropriate means which the United States may employ for exercising their delegated powers; the United States may not tax instrumentalities which a state may employ in the discharge of her essential governmental duties-that is those duties which the framers intended each member of the Union would assume in order adequately to function under the form of government guaranteed by the Constitution. ”
