Gentlemen of the Senate and of the House of Representatives:
I lay before you a report of the Secretary of State on the measures which have been taken on behalf of the United States for the purpose of obtaining a recognition of our treaty with Morocco and for the ransom of our citizens and establishment of peace with Algiers.
While it is proper our citizens should know that subjects which so much concern their interest and their feelings have duly engaged the attention of their Legislature and Executive, it would still be improper that some particulars of this communication should be made known. The confidential conversation stated in one of the last letters sent herewith is one of these. Both justice and policy require that the source of that information should remain secret. So a knowledge of the sums meant to have been given for peace and ransom might have a disadvantageous influence on future proceedings for the same objects.
George Washington, Special Message Online by Gerhard Peters and John T. Woolley, The American Presidency Project https://www.presidency.ucsb.edu/node/203368