The person who replaced William Jennings Bryan in 1915 as Secretary of State was Robert Lansing.
He was the United States Secretary of State from 1915 to 1920 under the presidency of Woodrow Wilson.
He took over from William Jennings Bryan who had resigned in 1915 because he did not support Wilson's inaction over the German sinking of the Lusitania.
Find out more on the sinking of the Lusitania at https://brainly.com/question/7190421.
