This is a district that has been trending towards the Republicans. The shift has been identified by some as coming from the changes in the that specific Orthodox Jewish community. Here is an article that studies the Jewish community in NY 9. The key take away is that as people age or leave, this community is becoming less and less the Jewish community that voted overwhelmingly Democratic.
http://www.capitalnewyork.com/article/culture/2011/09/3264144/turner-targets-conservative-leaning-jews-ninth-just-how-conservativeThe trend is strong enough that Kerry did better by a few points in a tough year than Obama did in a very democratic year, even though Dov Hikind (a NY assembly representative who has a radio show popular among the Orthodox Jewish population) and Ed Koch, a former Democratic mayor who has moved to the right endorsed Bush. In 2008, Koch endorsed Obama, but Hikind wrote a endorsement of McCain, that could have been ghostwritten by Sean Hannity! (
http://www.vosizneias.com/21734/2008/10/27/brooklyn-ny-hikind-obama-is-frightening-vote-mccain/ )
The leaders of this Orthodox community are EXTREMELY to the right on Israel. Some even to the right of Netanyahu - and this was a voting issue. They succeeded in making this a referendum on Obama's policy in Israel - ignoring that they are not typical of Jews - much less America! I actually wonder if the Democratic party erred in having robocalls to everyone from Cuomo and Bill Clinton. It might have been better to have Leiberman, who endorsed the Democrat, vouch for him on Israel and speak - in Jewish terms - of Tikkun Olam (repair of the world) which matches Democratic values better than tea party values.
The other issue was that the Democratic nominee had voted for NYS's gay marriage law. This was a courageous vote - and this district is a bit too socially conservative.