DS, one page, 11.5 x 17.5, August 13, 1855. Authorization to allow James J. O’Fallon to carry dispatches from the U. S. Legation in London to the U. S. Legation in Paris, signed at the conclusion in black ink by Buchanan. Buchanan served as minister to the Court of St. James’s (Britain) from 1853 to 1856, during which time he helped to draft the Ostend Manifesto, which proposed the purchase of Cuba from Spain in order to extend slavery. Toning and some slight separations and paper loss to fragile folds, and a few small edge chips, otherwise very good condition. Auction LOA John Reznikoff/PSA/DNA and R&R COA.