In the turmoil over the " ` Trent' affair," it was Sumner's word that convinced Lincoln that Mason and Slidell must be given up, and that reconciled the public to that inevitable step. Again and again Sumner used the power incident to his chairmanship to block action which threatened to embroil the United States in war with England and France.
In 1881 a harbour board was formed under the chairmanship of Mr Harry Escombe.
The members of the special boards under the chairmanship of the commissioner constitute a general board for all the hospitals, and the superintendent of each hospital is appointed by the general board.
He was active in debates and committee work, and for some time held the chairmanship of the important standing committee for the superintendence of the treasury, in which capacity he exercised a predominating influence on congressional expenditures.
In 1891, believing that his first duty was to his state, he resigned from the Senate to accept the chairmanship of the newly established state railway commission.