It is hardly news that the 'pro-Israel' (horrible phrase) lobby has a big influence on the US govt is it? On the other hand there are a lot of other lobbies that have a lot of influence as well.
Look I don't see it as a huge problem. Israel is the only real democracy in the middle east, the only nation in that region that doesn't have the death sentence for conversion away from Islam and the only nation that allows for non-muslims to have a significant share of power and land. Of all the countries to have a powerful lobby in the US from the middle east, far and away Israel is the least worrisome. I'm far more worried about the Saudi government because of their dismal human rights record. If there was a pro-Saudi test, yeah worry, because it means that you're looking the other way on Dhimmitude, oppression of women, and a death penalty for conversion from Islam. None of that is promoting the cause of liberty in the world. Israel is FAR from perfect, but considering the other players, Go Israel!