I don't know which of the candidates for president either John Mearsheimer or Stephen Walt support. After all, the three remaining (I know that there are really only two) presidential candidates spoke before AIPAC and each of them gave what I would call Zionist speeches. Good Zionist speeches. It will not surprise you that I thought Obama's was the best. But each of the talks was sophisticated, knowledgeable, and passionate. CNN telecasted all of them. These were not secret gatherings with the Elders of Zion.
AIPAC actually is the most open of American lobbies, and that is because its agenda is favored by most Americans. There are many reasons for this: historical, philosophical, strategic, know thy friend and know thy enemy. One thing you cannot say about this great majoritarian alliance is that it is covert.