Delano served as President Ulysses S. Grant's Secretary of the Interior during a time of rapid Westward expansionism, and contended with conflicts between Native tribes and White American settlers.

To compel the Native tribes to move to reservations, Delano supported the slaughter to the near extinction of the vast buffalo herds outside of Yellowstone, which were essential to the maintenance of the Plains Indians' way of life.

With the exception of Yellowstone, the spoils system and corruption permeated throughout the Interior Department during his tenure, and Grant requested Delano's resignation in 1875; he left office with his reputation damaged.

However, historians have strongly criticized Delano's weak oversight of the Interior, allowing rampant corruption, and for his treatment of Native Americans and endorsement of the Plains Indian bison slaughter.

[4] The following year Delano served as Commissary-General of Ohio, on the staff of Governor William Dennison Jr., and aided in raising and equipping troops for the Union Army at the start of the American Civil War.

[15] In September 1867, Delano made a speech on Reconstruction in Eaton, Ohio, in which he said that President Andrew Johnson did not have the constitutional authority to establish civil government in the former Confederate states.

[25] Unknown to Delano, on August 11, 1867, Grant had agreed to accept Johnson's offer to serve as interim Secretary of War, while simultaneously remaining general of the army.

[27] He also proved unwilling or unable to cope with the frauds of the Whiskey Ring; despite having received warnings of corruption including bribery of federal officials and failure to pay taxes, Delano took little or no action.

[35] 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.

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.

[38] On November 10, 1871, Delano advocated Grant that Apaches be given new reservation land in Arizona and New Mexico, following the recommendation of Indian Peace Commissioner Vincent Colyer to find them a location where they could be protected from attacks by white settlers.

Delano stated that Hayden's expedition was directed to "...secure as much information as possible, both scientific and practical...give your attention to the geological, mineralogical, zoological, botanical, and agricultural resources of the country.

[53] In March 1871, Grant signed into law Congressional legislation that established the United States Civil Service Commission, designed to create reform rules and to regulate and reduce corruption in the federal workforce.

Grant's second Attorney General Amos T. Akerman, a former Confederate soldier, knew of the outrages of the Klan and was zealous in prosecuting white Southerners who terrorized their black neighbors.

[62] In a campaign speech supporting President Grant's reelection bid in Raleigh, North Carolina, on July 24, 1872, Delano spoke out in favor of prosecutions of the Ku Klux Klan.

In addition, Christian organizations and missionaries operating on these reservations could "civilize" the Native Americans, in line with the widespread belief (including Delano's) that allowing the Indians to continue to practice their own culture would lead to their destruction.

[69] Grant sent the expedition, hoping to find gold in order to support his species currency policy; Delano opposed the move, believing travel through and eventual occupation of hunting grounds violated the Treaty of Fort Laramie and could lead to an Indian war.

[70] Whites immediately flocked to the area in search of gold; in 1875, Congress appropriated $25,000 (~$631,560 in 2023) for the purchase of the Black Hills, hoping that a cash payment would assuage the Sioux and prevent war.

In mid-May 1875, Red Cloud, Chief of the Oglala Lakota (Sioux), and other Indian tribal leaders were brought to Washington D.C. to negotiate the sale of the Black Hills.

[74] Grant told Red Cloud that the Black Hills had no buffalo, so it would benefit the Indians to accept payment because they would at least receive something of value in consideration for signing away valueless hunting rights.

[75] With Red Cloud's refusal, Delano reluctantly let the Indians take the unsigned agreement back to their tribal agencies for further discussion among the members of the tribe, with final terms and signatures to be negotiated later by an appointed commission.

Upon their return to Sioux country, Red Cloud and other Lakota leaders finally signed away their hunting rights to the Black Hills under Article 11 of the Treaty of Fort Laramie in exchange for the original $25,000 Congressional appropriation.

Another group of Sioux chiefs, including Sitting Bull and Crazy Horse, challenged Red Cloud's authority and started the armed resistance about which Delano had warned Grant.

[77] This challenge to Red Cloud's authority combined with Lakota unhappiness over white encroachment into the Black Hills resulted in the Great Sioux War, which started in February 1876.

Belknap, who had awarded Orvil Grant the four traderships, took advantage of the law to personally profit by arranging an illicit partnership at Fort Sill between his wife Carrie, Caleb P. Marsh, and sutler John S. Evans.

[112][113] Delano has also received criticism for allowing millions of bison to be slaughtered, with the exception of Yellowstone, in order to compel the Indians to move to and remain on their reservations, a policy approved by President Grant and the U.S.

Among its features, it outlawed poaching wildlife and served as a haven for small numbers of free-roaming bison, left after the slaughter of the great herds that, with the exception of Yellowstone, Delano had fully supported.

[119] In January 1883, President Arthur signed into law the landmark legislation, known as the Pendleton Act, that made civil service reform permanent, with the goal to reduce corruption and hire persons based on a merit system, rather than patronage.

[124] In 1898, historian Joseph Patterson Smith said Delano had attained, "a long and distinguished career, as an eminent lawyer, an able businessman and one intimately identified with the governmental affairs of the state and nation.

"[3] In 2001, historian Jean Edward Smith, taking a harsher view, said Delano betrayed his public trust while Secretary of the Interior by allowing corruption to pervade throughout his department, "at the expense of those who most needed government assistance: the Native American.