Foreign policy scholars often assume that leaders pursue a national interest. However, states often spread their foreign policy authority thinly across bureaucracies and programs with overlapping or conflicting interests. This is especially pronounced in foreign aid, which serves a clear foreign policy purpose but is often mired in bureaucracy. Why is foreign aid often so fragmented? Focusing on the United States, I explain foreign aid fragmentation as a byproduct of domestic politics. When moderate legislators are ideologically diffuse, leadership must persuade them to support a foreign aid agenda by offering pet projects. This increases aid’s fragmentation. In contrast, when moderates are relatively homogeneous, leaders can gather support through more traditional compromise, decreasing the need for fragmented pet projects. I test this theory using a mixed-methods approach, employing a novel agency-level dataset of US foreign aid appropriations and a case study of a 1992 act delivering aid to the former Soviet Union.