Ambassador (later Secretary of State) John Hay's remark that the American war with Spain in 1898 was a ‘splendid little war’ is well known. His next phrase, ‘begun with the highest motives’ is not. President William McKinley repeatedly defined the war as humanitarian. It was ‘a triumph of our humanity’ begun ‘for freedom and to relieve our neighbors of oppression’. One recent commentator sees in human rights ‘one of the primary reasons why the United States went to war with Spain’, although this ignored ‘the contradiction inherent in the joint pursuit of democracy, a dynamic concept, and stability, a static one’. In September 1949, Secretary of State Dean Acheson commented on commitments in Latin America: ‘to protect security, defend democracy, and refrain from intervention in the internal affairs of other American nations, a prescription, it might seem, for inaction … or sacrifice of one of our purposes or principles in pursuing others’. The McKinley administration went to war to free Cuba. It then limited freedom in former Spanish colonies. I shall argue that a core of humanitarian principles informed both decisions, but also stimulated opposition to the second.

Intervention presented as purely self-interested or purely humanitarian did not command enough support to force war.