In the Senate, Thurman served on the Judiciary Committee, becoming its chairman when the Democrats won control of the Senate in the 46th Congress. He also became President pro tempore of the Senate briefly, serving as president of the Senate because of the illness of Vice-President William A. Wheeler, before Ohio chose a Republican legislature, which would not reelect Thurman. They first chose Garfield, but on his election to the Presidency, selected John Sherman to succeed Thurman beginning in 1881. Garfield did appoint Thurman as American representative to the international monetary conference in Paris, a selection that Republican senators welcomed: they regretted his departure from among them. It was noted that in twelve years in the chamber, he had never had an angry word with any colleague, and noted, too, that he left the Senate as poor as he had come to it.