On 4 November 2019, Ambassador Robert O’Brien, Assistant to the President of the United States of America for National Security Affairs, in his capacity as Special Envoy of the President and Head of the United States of America delegation to attend the 35th ASEAN Summit and Related Summits, paid a courtesy call on H.E. General Prayut Chan-o-cha, Prime Minister of the Kingdom of Thailand. Special Envoy O’Brien delivered an official note from President Trump commending Thailand’s role as ASEAN Chair as well as discussed on strengthening their bilateral relations and cooperation.