Edward Douglass White

“ The duty to be enforced by mandamus must not only be merely ministerial, but it must be a duty which exists at the time when the application for the mandamus is made. Thus in the case of Ex parte Rowland, 104 U.S. 604, this court, speaking through Mr. Chief Justice Waite, said: 'It is settled that more cannot be required of a public officer by mandamus than the law has made it his duty to do. The object of the writ is to enforce the performance of an existing duty, not to create a new one.'
Moreover, the obligation must be both peremptory, and plainly defined. ”

“ We cannot perceive any duty which under these circumstances rested upon the secretary of war to sign such a contract with the relator as would be required by the mandamus which is prayed. It cannot be reasonably contended that he is under any obligation to sign two contracts with the same person for the same work at a different price and under different conditions. ”

“ We deem the consideration of both these points unnecessary, in view of the relator's bids under the second advertisement and specifications, and his contract to do the work at a less price and under new conditions. It is elementary law that mandamus will only lie to enforce a ministerial duty, as contradistinguished from a duty which is merely discretionary. ”