I am opposed to raising the elevation of the guns on United States battleships for reasons I have already given. I don't know why there is constant agitation about that, unless it be the result of an attempt to try and break down our system of limitation of armaments and resort to the old policy of competition. Now, I don't think it is a question of whether by a technical construction of the treaty we have a right to elevate these guns. Suppose we have; suppose we haven't. If we are going to have the policy here of limitation of armaments, we shall never have it by reason of that treaty we have made, but by reason of a public sentiment that exists in the country in favor of that policy. If you break down the public sentiment you will begin to dig down under the treaties that are in existence at the present time, and when you get far enough under them they will explode something and destroy them. That is the main reason why I am opposed to the elevation of the guns. $8,000,000 is not a large sum to expend for the elevation of guns, but the work will extend over some years. Then these ships, as I have already explained, will become obsolete in a short time, and our naval treaty lasts ten years and is drawing to a close. I think it is much more important to do what we can to promote sentiment here as in favor of limitation of armaments and against competition than in that direction. Otherwise, we will be right back in the place that civilization has found itself ever since it began and an inability to rely on anything except the number of guns that it has for the protection of its interests. I am desirous of promoting the other policy, so I am opposed to elevating the guns at this time. I think it would be hailed as the beginning of the breaking down of that policy. I am sending up to the Senate in response to their resolution, a copy of the letter which Secretary Hughes, after consulting with me, had already sent to the Committee on Naval Affairs in the House, which gives all the information and some other information that the Senate has requested. Japan as I understand it doesn't think it is contrary to the terms of the treaty, but the British have raised that question.
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/349087