Somebody by the name of Joseph Epstein has a fascinating piece on what it is like to the that most incongruous of people, a Jewish Republican: http://online.wsj.com/article/SB122143719228934301.html?mod=djemEditorialPage. He's right, too. Other than perhaps African Americans, no group is identified more with the Democratic Party than Jews, going back to the days of Franking Delano Roosevelt.
The thing is, that Democratic Party is not today's party, which has taken a fairly sharp turn to the left and which is now home to many people who don't hold what I would call "Traditional Jewish Interests". For example, Jews are high achievers, by and large, yet the Democrats stridently support quotas which have the effect, albeit unintended, of keeping them out of certain positions. Jews support Israel by an overwhelming majority, yet the Democratic Party is home to the President Peanut Farmer ("Israel is an apartheid state!") and the denizens of the Daily Kos and Moveon.org, who regularly and loudly villify Israel in the most vile language.
Those are but two examples, and I don't know that anyone will agree with either Mr. Epstein or myself, but it's interesting nonetheless.