David Mark at Politico has an article titled, "Obama slow to gain among Catholics":
"[O]ne potentially critical set of voters remains stubbornly resistant to his appeal-Catholics. In state after state, with only a few exceptions, exit polling shows Hillary Rodham Clinton is the choice of Catholic voters. Clinton even defeated Obama among Catholics in his home state of Illinois. It seems the more Catholic the state, the more likely she is to have won it. ... Clinton's strength with Catholics is in part driven by her popularity with Hispanics, many of whom are Catholic."
Read Here: http://www.politico.com/news/stories/0308/8781.html