As a statesman, he is generally regarded as a failure, and his deep hostility to the newly independent United States damaged relations between the two countries.

[1] Early in 1783, Carmarthen was selected as ambassador to France, but he did not take up this appointment, becoming instead Secretary of State for Foreign Affairs under William Pitt the Younger in December of the same year.

[1] Historian Jeremy Black says that in terms of foreign policy, Pitt and other leaders were disappointed with his performance as a minister.

[5] Subsequently, Leeds took little part in politics: in 1792, hearing rumours that a new coalition might be formed, he unwisely offered himself as its head and met with a firm rebuff from both Pitt and the King.

Leeds's Political Memoranda were edited by Oscar Browning for the Camden Society in 1884, and there are eight volumes of his official correspondence in the British Museum.