"The animating principle of my faith, as taught to me by church and home, was that the cardinal sin was abuse of power," he said in an interview with the Monitor. "It was not only required as a good Catholic to abhor and avoid abuse of power, but to do something to end that abuse."

Biden says he grew up feeling at home in the church. In the Irish neighborhoods in Scranton, Pa., where he spent most of his weekends, a majority of the kids were Catholic. Neighbors attended mass, and nuns and priests were a respected part of daily life. "Wherever there were nuns, there was home," he writes in a new book on his life and politics.

Biden is troubled, too, by ongoing sexual-abuse scandals involving children within the church. But he says his commitment to church remains unchanged. "This is my church as much as it is the church of a cardinal, bishop, or janitor, and I'm not going anywhere," he said. "I care a great deal about my faith."