Connie Bruck, who writes regularly on business and politics for the New Yorker, has a run down on AIPAC's history and influence on U.S. policy toward Israel. She points to some recent setbacks in its lobbying (on Iran, negotiations, and sanctions), but over-all she illustrates that it is a formidable influence not only in Washington but everywhere anyone runs for national office. More formidable she says than the NRA.
One congressman, who gave up, points out how hard it is to vote in the U.S. national interest when AIPAC is on your case. "Friends of Israel" @ the New Yorker.