For over three decades the American Israel Public Affairs Committee (AIPAC) has been an effective lobby within Congress to ensure that Israel remains strong militarily and economically, and endures as a national homeland for Jews. While acknowledging its effectiveness, AIPAC critics maintain that AIPAC is an ex-officio arm of the Israeli government which shamelessly manipulates the political process whenever it decides that there is a perceived threat to Israel’s interests. This paper will examine AIPAC’s origins, its structure and agenda. and its lobbying techniques to better understand why AIPAC is considered by many to be the most influential Congressional lobby.