thumb|left|Belgian Legion fighting in Mexico In 1861, the American Civil War commenced and despite Belgian neutrality, Leopold was in favour of the Confederate States due to economic the United States Union's imposition of economic blockades, including the refusal to export South American goods to Europe. According to historian Francis Balace, Leopold played an important role as a mediator between the United States and the rest of Europe, as well as in convincing other European states to back the South. In contrast, historian Jacques Portes has downplayed the significance of Leopold's role by painting him as an ineffective transmitter of correspondence between the two sides with little care for Belgium's impartiality.
thumb|left|Belgian Legion fighting in Mexico In 1861, the American Civil War commenced and despite Belgian neutrality Leopold was in favour of the Confederate States due to economic the United States Union's imposition of economic blockades, including the refusal to export South American goods to Europe According to historian Francis Balace, Leopold played an important role as a mediator between the United States and the rest of Europe, as well as in convincing other European states to back the South. In contrast, historian Jacques Portes has downplayed the significance of Leopold's role by painting him as an ineffective transmitter of correspondence between the two sides with little care for Belgium's impartiality