Middleton served as Minister to Russia (1820–1830), being sent there in the first instance to replace George Washington Campbell, so as to look after interests in the discussions preparatory to arbitration by Czar Alexander I on the question of compensation under Article 1 of the Treaty of Ghent as regards enslaved Americans who went away with British during and after the War of 1812.Harold E. Berquist, Jr (1981): Henry Middleton and the Arbitrament of the Anglo-American Slave Controversy by Tsar Alexander I, The South Carolina Historical Magazine Vol. 82, No. 1 (Jan. 1981), pp. 20-31
