In this photo provided by the Vatican newspaper L'Osservatore Romano, Pope Benedict XVI, right, receives the letter of credentials from the new U.S. ambassador to the Holy See, Miguel H. Diaz, a university theology professor who is a Roman Catholic, in the papal summer residence in Castel Gandolfo, on the outskirts of Rome, Friday, Oct. 2, 2009. Benedict XVI pledged on Friday that the U.S. Catholic church will keep working to shape American consciences on ethical questions such as abortion as he praised the United States for its "vibrant" democracy. The pontiff said that he was confident the two sides would continue to enjoy "fruitful dialogue and cooperation in the promotion of human rights, and the service of justice, solidarity and peace." Vatican teaching forbids abortion, and Catholic bishops have been at the forefront of American anti-abortion movements. Some of the prelates have threatened to withhold Communion from Catholic politicians who support legalized abortion. (AP Photo/L'Osservatore Romano, HO) EDITORIAL USE ONLY