If you believe Jewish Americans are single-issue voters, and that issue is support for the Israeli occupation, then it makes sense to ask, as Norman Podhoretz does in a new book and Commentary symposium, "Why are Jews Liberal?"
But this is a fundamental misreading of the political commitments of American Jews, 92 percent of whom describe issues other than Israel as their primary concern. According to one election season poll, the top two issues for American Jews are the economy and the Iraq war.
In his Times Magazine profile of J-Street, a PAC seeking to advance progressive views on Israel, James Traub does a good job of describing the difficulty of representing the political opinions of "the dispassionate many" on Israel, as opposed to the "passionate few" represented by AIPAC. So in one sense, Jewish neo-cons will always have a voice louder than more typical Jews when it comes to Israel, because they simply care much more. That doesn't mean they represent the community.
Why are Jews actually liberal? In the the Commentary forum, only Rabbi David Wolpe states the obvious, attributing Jewish liberalism, as I do, to our deep identification with the marginalized and oppressed:
...I suspect until conservatism convinces most Jews that they have a sympathy and practical program for those who are real or putative outsiders, it will remain, among Jews at least, distinctly the minority movement.
Interestingly, this outlook -- the attachment to the Jewish history of oppression -- is responsible for both the liberal and conservative strands of contemporary Jewish politics. The liberal strand lends support to programs that help the poor, such as universal health care and immigration reform. The conservative strand uses the reality of anti-Semitism to justify Israel's inhumane policies toward Palestinians and Arab-Israeli citizens.