killed by Native American warriors, Sherman telegraphed Grant that "we must act with vindictive earnestness against the Sioux, even to their extermination, men, women and children." In 1867, he wrote to Grant that "we are not going to let a few thieving, ragged Indians check and stop the progress" of the railroads. In 1873, Sherman wrote in a private letter that "during an assault, the soldiers can not pause to distinguish between male and female, or even discriminate as to age. As long as resistance is made[,] death must be meted out, but the moment all resistance ceases, the firing will stop and all survivors turned over to the proper Indian agent". Displacement of the Plains Indians was facilitated by the growth of the railroads and the eradication of the bison. Sherman believed that bison eradication should be encouraged as a means of weakening Indian resistance to assimilation. He voiced this view in remarks to a joint session of the Texas legislature in 1875, although the U.S. Army under Sherman's command never conducted its own program of bison extermination. Sherman encouraged bison hunting by private citizens and, when Congress passed a law in 1874 to protect the bison from over-hunting, Sherman helped convince President Grant to use a pocket veto to prevent it from coming into force. General of the Army When Grant became president in 1869, Sherman was appointed Commanding General of the United States Army and promoted to the rank of full general. After the death of John A. Rawlins, Sherman also served for one month as acting Secretary of War. Sherman's early tenure as Commanding General was marred by political difficulties, many of which stemmed from disagreements with Secretary of War Rawlins and his successor, William W. Belknap, both of whom Sherman felt had assumed too much power over the army and reduced the position of Commanding General to a sinecure. Sherman also clashed with Eastern humanitarians who were critical of the army's harsh treatment of the Indians and who had apparently found an ally in President Grant. To escape from these difficulties, Sherman moved his headquarters to St. Louis in 1874. He returned to Washington in 1876, when the new Secretary of War, Alphonso Taft, promised him greater authority. Much of Sherman's time as Commanding General was devoted to making the Western and Plains states safe for settlement through the continuation of the Indian Wars, which