Excellent documentary about this taboo subject. It includes input from people on all sides of the discussion. The big question is whether 'The Lobby' is only allowed influence so long as its interests coincide with US interests, or whether Israel is effectively controlling US foreign policy in the region
The Israel Lobby. Portrait of a Great Taboo
Note: the narration is in Dutch but all of the interviews are conducted in English so don't be deterred by the Dutch language introduction (two/three minutes approx).