Melville Fuller,
United States Boynton v. Blaine…
“ The writ of mandamus cannot issue in a case where its effect is to direct or control the head of an executive department in the discharge of an executive duty involving the exercise of judgment or discretion. U.S. v. Windom, 137 U.S. 636, 644, ante, 197. When by special statute, or otherwise, a mere ministerial duty is imposed upon the executive officers of the government, that is, a service which they are bound to perform without further question, then, if they refuse, the mandamus may be issued to compel them. ”
