It should be noted that, IIRC, Yonkers voted slightly to the right of Westchester County in 2008.
I doubt that very many Hasidim will move to Scarsdale--it is quite an expensive place and the Hasidim tend to be more lower income.
I guess you are not familiar with NYJew's posts.
That house in my signature is in Brooklyn, and the precinct it is in (99.5% white - it has 2 Hispanics and 2 Asians in it and 0 blacks per the 2010 census) voted 84% for McCain by the way. It's clear, that if the Hasidim, or whatever the particular Orthodox Jewish sect, really want to live somewhere, they will outbid everybody else for the housing stock. They mean business!