This chapter discusses American foreign policy and Irish nationalism from 1865–70. Organised in 1853 by James Stephens in Ireland and John O'Mahony in the US, the aim of the Irish Republican Brotherhood (IRB) was to supply money and arms to achieve an independent Irish republic. In August 1865, O'Mahony ordered his officers to Ireland and a military intervention was planned for October. Even before they left, many were under surveillance which continued after arrival when several were arrested and more were harassed by Irish Constabulary detectives. Two categories of prisoner emerged: those interned on the Lord Lieutenant's warrant during the suspension of the Habeas Corpus Act (1679) and those against whom there was sufficient evidence for a trial. In both cases, the Americans turned to their consul for protection and once again Irish nationalist activity came to the centre of American–British relations. The quiescent issues of citizenship, naturalisation and US government tolerance of anti-British activities on its soil and the related threat to British control of Ireland, were revived.