Further astonishment was caused by the attitude of the President toward two of the three really able men in his cabinet. In June, 1870, he suddenly called for the resignation of Judge Hoar. It appeared that he was seeking votes in the Senate for a treaty in which he was interested and that certain southern members demanded the post of attorney-general for a southern man in return for their support. Secretary Cox's resignation came soon afterward. He had taken his department out of politics, had furthered the cause of civil service reform and had protected his employees from political party assessments. These acts brought him into collision with the politicians, who had the ear of the President, and Cox had to retire. Both Hoar and Cox were succeeded by mediocre men. The treaty which caused the removal of Secretary Hoar was one that the President had arranged providing for the annexation of San Domingo. The Senate was opposed to ratification, but General Grant was accustomed to overcoming difficulties and he urged his case with all the power at his command. One result was an unseemly wrangle between the President and Senator Charles Sumner over the latter's refusal to support ratification. General Grant, in resentment, procured the withdrawal of the Senator's friend, John Lothrop Motley from England, whither he had been sent as minister, and later the exclusion of Sumner from the chairmanship of the Committee on Foreign Relations, a post in which he had displayed great ability for ten years. Eventually the President had to give way on San Domingo, as the Senate did not agree with him in his estimate of its probable value.