Excerpts of the President's News Conference
I don't know that I shall have any special message to the Republican National Convention, other than to suggest to them that they make their own choice of Vice-President. I think that was the course that Roosevelt adopted in 1904. It seemed to work very well then, and that is the course I am going to adopt in the coming Convention. The delegates will assemble from all over the country. They know what the general feeling of the country is better than I can judge of that, and I very much prefer to have them make the choice of a candidate for Vice-President, than to undertake to make one myself.
Source: "The Talkative President: The Off-the-Record Press Conferences of Calvin Coolidge". eds. Howard H. Quint & Robert H. Ferrell. The University Massachusetts Press. 1964.
Calvin Coolidge, Excerpts of the President's News Conference Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/349056