Hoar disagreed and decided in favor of New Idria, which prompted Grant to request their resignations. Grant appointed Delano to succeed Cox at the Interior Department; he served from November 1, 1870, until resigning on October 19, 1875. During Delano's tenure, the Interior Department was the largest bureaucracy in the federal government, including numerous patronage positions. Running the department required knowledge of dissimilar duties, and the ability to master complex details. During Delano's time as secretary, he faced several critical issues and his department was rapidly expanding; despite the challenges he served longer in the job than any other 19th-century incumbent. Delano aligned himself with Grant's private secretary Orville Babcock and Secretary of Navy George M. Robeson. Delano rejected the civil service reforms of his predecessor Cox and reverted the Interior to the spoils system. Bison slaughter (1870s) During the Civil War, Union generals practiced a "scorched earth" campaign against Confederate infrastructure that destroyed its vital food supplies, which aided in bringing about the Union's victory. During the late 1860s and early 1870s U.S. Army officers William T. Sherman, Richard Dodge, and Secretary of the Interior Delano adopted a similar strategy against Native Americans in the west, whose primary food supply was free-roaming bison. Dodge said in 1867, "Every buffalo dead is an Indian gone." Delano said in an 1872 annual report, "The rapid disappearance of the game [bison] from the former hunting-grounds must operate largely in favor of our efforts to confine the Indians to smaller areas, and compel them to abandon their nomadic customs." Much of the destruction of bison was done by private, for-profit buffalo hunters; this policy allowed the slaughter of millions of bison on the American plains, forcing Indians to move to and remain on their reservations. The few free-roaming bison left in Yellowstone were protected from poaching by a federal law passed in 1872; during Delano's tenure, mounting criticism by the public forced Congress to pass legislation that would stop the bison slaughter on the plains. Grant vetoed the legislation in 1874, accepting that the bison slaughter was accomplishing the goal of pacifying the Indians. From 1872 to 1874 the Indians killed approximately 1,215,000 bison as part of providing for their food, shelter, and other basic needs; American hunters slaughtered an estimated 4,374,000 bison, reducing the population to the point that it could not reproduce normally and continue to sustain the Indians. Apache massacre