By tackling the subject in a book to be published March 10, Benedict, whose has struggled in his relations with the Jewish community, doesn't so much state something new the affirmation that the Jewish people as a whole were not responsible for the crucifixion is an old one, uncontroversial in the modern Catholic Church as lend the idea the ecclesiastical equivalent of a celebrity endorsement. "The significance is in the author," says Joseph Sievers, professor of Jewish history at the Pontifical Biblical Institute in Rome. "