On January 26, 1894, President Grover Cleveland (the former mayor of Buffalo and governor of New York) appointed Buchanan United States Minister to Argentina. He presented his credentials on May 19, 1894, and served until he left his post on July 11, 1899.[4] He also served as arbitrator on the special commission to fix the boundary between the Chilean and Argentine governments.[5] After William McKinley became president, he kept Buchanan on, even though he was a Democrat and the new president was a Republican. Once Panama separated from Colombia in 1903, he was appointed by President Theodore Roosevelt on December 17, 1903, to serve as United States Minister to Panama.[4] Buchanan presented his credentials as Envoy Extraordinary and Minister Plenipotentiary on special mission in December 1903, however, "he received new credentials as Envoy Extraordinary and Minister Plenipotentiary only a few days before he was to leave Panama and apparently did not present them. He ceased to act "on special mission," however, and conducted business in the capacity of Envoy Extraordinary and Minister Plenipotentiary until his departure."[4]
Later career
Buchanan was Director General of the Pan-American Exposition, held in Buffalo, New York, from May 1 through November 2, 1901, and is credited with the construction, operation, and dismantling of the exposition.[6] He was chosen by John G. Milburn, president of the exposition, as the exposition was planned with a Latin American theme and they wanted someone who knew the South American countries well.[3] President McKinley was assassinated at the exposition by anarchist Leon Czolgosz on September 6, 1901, and Roosevelt traveled to Buffalo where he was inaugurated shortly thereafter.[7]
Buchanan was married to Laura "Lulu" Williams (1855–1928), a daughter of John Insco Williams and Mary (née Forman) Williams. Together, they were the parents of:
Florence Buchanan (1879–1941), who married Charles Hoyt Williams.[8]