At the 1852 Democratic National Convention, he won the support of many southern delegates but failed to win the two-thirds support needed for the presidential nomination, which went to Franklin Pierce. Buchanan declined to serve as the vice presidential nominee, and the convention instead nominated his close friend, William R. King. Pierce won the 1852 election, and Buchanan accepted the position of United States Minister to the United Kingdom.[29]
Buchanan sailed for England in the summer of 1853, and he remained abroad for the next three years. In 1850, the United States and Great Britain signed the Clayton–Bulwer Treaty, which committed both countries to joint control of any future canal that would connect the Atlantic and Pacific Oceans through Central America. Buchanan met repeatedly with Lord Clarendon, the British foreign minister, in hopes of pressuring the British to withdraw from Central America. He also focused on the potential annexation of Cuba, which had long interested him.[30] At Pierce's prompting, Buchanan met in Ostend, Belgium, with U.S. Ambassador to Spain Pierre Soulé and U.S. Ambassador to France John Mason. 