Jews? You mean the same Jews that regularly elect people like Keith Ellison?
Yes Jews, especially seniors who are common in Florida. Obama does terrible among Jews for a Democrat. Whereas Democrat candidates usually get 80% at least of the Jewish vote, Obama can be glad to get 50-60% at best. McCain is very attractive to Jewish voters, and he can pull an Ike or Reagan in this case (Ike was the GOP candidate with highest % of Jewish votes methinks, Reagan had 40something %. Bush 2000 had IIRC 10% but 2004 30something %). So while a slim majority of Jews probably will vote Democrat, the loss of a lot of their votes can spell doom for Obama in swing states.