Catholics are the largest religious community in Pennsylvania, making up 29% of the state’s adult population, followed by mainline Protestants at 25% and evangelical Protestants at 18%; white Catholics have been a pillar of Hillary Clinton’s voter coalition in her big-state victories to date and are likely to be an important factor in the outcome of tomorrow’s primary. Recent state polls suggest that Clinton enjoys a huge lead among white Catholics in Pennsylvania, and that is likely one of the reasons she has been consistently ahead. Obama has been working to expand his support beyond younger and more affluent Catholics, who have backed him in other states, to include older and blue-collar Catholics who have tended to support Clinton. Something like this happened in two large, industrial states where Obama won. In Missouri, Clinton had a small 50%-to-46% advantage among white Catholics, and in Wisconsin Obama edged Clinton 50% to 49% with this group. Read More

Russell Heimlich  is a former web developer at Pew Research Center.