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  • "Global Governance: From Pacem in Terris to Caritas in Veritate," paper presented to the Pontifical Academy of Social Sciences for the plenary meeting The Global Quest for Tranquillitas Ordinis: Pacem in Terris, Fifty Years Later, Vatican City, April 27, 2012.
  • "The Pillars of Catholic Social Thought," lecture for international seminar Catholic Social Teaching, Business and Morality hosted by the Acton Institute, Rome, November 18, 2011. †
  • "The 'Subjectivity' of Work in Catholic Social Doctrine," lecture for international seminar Catholic Social Teaching, Business and Morality hosted by the Acton Institute, Rome, November 18, 2011. †††
  • "The Future of Ecumenism: A One-Hundred-Year Forecast," talk given for the International Summit of the Springtime of Faith Foundation, University of Dallas, Rome, November 11, 2011.
  • "The Originality of John Paul's Theology of the Body," paper delivered for the International Conference on the Theology of the Body at the Regina Apostolorum Pontifical Athenaeum, Rome, November 10, 2011.
  • "The New English Translation of the Roman Missal," talk given in Rhode Island, August 8, 2011.
  • "Un-Conventional Rights: Children, Parents and the State," paper delivered for the international conference Foundations of Human Rights: Catholic Contributions, Ave Maria University (Naples, FL), March 3, 2011.
  • "Moral Relativism and the Future of Western Society," paper presented in Rome, February 8, 2011.
  • "Meet the God-Slayers: The New Atheistsí Fixation with Religion," talk for the East Detroit chapter of Legatus, January 25, 2011.
  • "Trust and Christian Spirituality," talk given for the Detroit chapter of Legatus, January 11, 2011.
  • "Evangelizing the Media," lecture given to the International Leadership Seminar, Rome, October 11, 2010.
  • "Media Subjectivity and the New Evangelization," New Orleans, August 27, 2010.
  • "Politics and Religious Discernment," paper delivered for Campus Martius in Rome, February 24, 2010.
  • "Benedict XVI and Catholic Social Thought," paper delivered to the New York chapter of the Lumen Institute, February 4, 2010.
  • "The Future of Catholic Social Doctrine," paper delivered in Badmünstereifel, Germany, December 28, 2009.
  • "God and Religion in the Crosshairs: The New Atheism," paper delivered to the Dublin chapter of Legatus, 17 November 2009.
  • "Conscience, Relativism and Moral Truth: Does Objective Morality Exist?" paper delivered at the annual meeting of the World Union of Catholic Women's Organizations, Rome, 16 November 2009.
  • "Governing the City: Applied Subsidiarity," paper delivered to the Scuola di Formazione socio-politica, Milan, 14 November 2009.
  • "Caritas in veritate: Whither Catholic Social Doctrine?" paper delivered to the national men's convention of Regnum Christi, Cheshire (CT), 10 October 2009.
  • "Biblical and Secular Morality: Similarities and Differences," paper delivered to professors and students of the Universität Witten/Herdecke, Witten, Germany, June 2, 2009.
  • "The Year of the Priest and the Triplex Munus," paper delivered to members of the Institut du Bon Pasteur, Rome, May 26, 2009.
  • "Becoming People of the New Springtime," address given to participants of Springfest 2009, Nashville, TN, May 17, 2009.
  • "Three Paradigms of Prudent Decision-Making," paper delivered to a meeting of the Lumen Institute at The Harvard Club, New York, April 24, 2009.
  • "The Vatican of the 21st Century," address given for a meeting of CEOs at the Hassler Hotel, Rome, April 20, 2009.
  • "Dalla crisi finanziaria alla crisi reale: Riflessioni tra etica ed economia," paper presented in Milan, Italy, April 7, 2009.
  • "Law and Respect for Human Dignity," paper delivered at Matercare's 5th International Conference for Catholic Obstetricians and Gynaecologists The Hope for Motherhood and the Ethical Practice of Obstetrics, Rome, November 6, 2008.
  • "Nuove sfide contro la vita: Come i problemi morali diventano problemi sociali," lecture given at the Centro San Carlo (Milan), November 3, 2008.
  • "A Universal Foundation for Universal Rights," paper delivered for the international conference For Everyone, Everywhere: Universal Human Rights and the Challenge of Diversity organized by the U.S. Embassy to the Holy See at the Istituto Maria Santissima Bambina (Rome), October 16, 2008.
  • "Theology of the Body and Humanae Vitae," paper delivered for the Third Annual Theology of the Body Conference titled Does Marriage Matter? held at the Park Inn Hotel, Dublin, Ireland, October 4, 2008.
  • "Conscience, Your Morals and Mine," paper delivered for the Theology on Tap series, Manhattan, New York, September 29, 2008.
  • "The Presumption Against Violence: An Ethical Analysis," paper delivered as part of the John Henry Cardinal Newman Lectures entitled Violence, Forgiveness and the Moral Order, at the Cosmos Club, Washington, D.C., April 25, 2008.
  • "La famiglia alla luce della dottrina sociale della Chiesa," paper delivered at a gathering of Crescere in famiglia in Modena (Italy), April 12, 2008.
  • "La vérité nous rendra vraiment libres ?", paper delivered at the Congrès Nationale, Abidjan (Côte D'Ivoire), April 4, 2008.
  • "Business as a Vocation," paper delivered for the Acton Institute seminar on Business and Morality at the Palazzo Cesi (Rome), February 29, 2008.
  • "The Church and Economic Development," paper delivered at the Acton Institute international seminar Has International Development Failed the Poor? Populorum Progressio 40 Years Later, at the Pontifical Athenaeum Regina Apostolorum, February 28, 2008.
  • "A New Springtime for the Catholic Church in the United States," a paper delivered at the international seminar Springtime of Faith, Savoy Hotel (Rome), November 10, 2007.
  • "The One and the Many: Unity, Diversity and the Common Good," paper delivered at the international conference The Foundations of a Free Society, Pontifical Lateran University, May 2, 2007.
  • "The Dawkins Delusion," paper delivered for Theology on Tap (Rome), March 22, 2007.
  • "Deus caritas est: aspetti pastorali", paper delivered at the European University of Rome, February 27, 2006.
  • "Insufferable Semantics: The Myth of Religious Tolerance," paper delivered at the international conference "Religious Liberty and Relativism" held by The Becket Fund for Religious Liberty to commemorate the 40th anniversary of the Vatican II Declaration on Religious Liberty Dignitatis humanae, Rome, Italy, December 10, 2005.
  • "La libertad y la tiranía mediáticas," lecture given at the 8th international conference on Catholics and Public Life, held at the Universidad San Pablo CEU, Madrid, Nov. 18, 2005.
  • "Evangelización y medios de comunicación social," UPRA, Roma, October 13, 2005.
  • "La verità vi farà liberi: Tolleranza, evangelizzazione e dialogo," lecture given at the Regina Apostolorum University, Rome, October 12, 2005.
  • "The Inner Workings of the Conclave," lecture to students and faculty of Duquesne University, Rome, Italy, April 17, 2005.
  • "The Least of my Brethren: The Ethics of Heterologous Embryo Transfer," paper presented at the international academic conference Global State of Stem Cells and Cloning in Science, Ethics and Law, Rome, Italy, March 7-8, 2005.
  • "Why Socrates Was Wrong: Moral Theology and Original Sin," paper presented in the academic conference Il peccato originale: Una prospettiva interdisciplinare, Rome, Italy, March 3-4, 2005.
  • "The Renewal of Mariology," lecture given on December 4, 2004 for the presentation of Father Paul Haffner's book The Mystery of Mary, Regina Apostolorum Pontifical Athenaeum, Rome, Italy.
  • "Terrorism and International Law: A Catholic Perspective," lecture given at the academic conference Revitalizing International Law to Meet the Challenge of Terrorism, sponsored by the United States Embassy to the Holy See and the Pontifical Gregorian University, and held at the latter in Rome on April 22, 2004.
  • "Libertà, maturità, coscienza: Sfide per la nuova evangelizzazione nel terzo millennio," Padua, Italy, November 23, 2003.
  • "Animalismo, difesa dell'ambiente e diritti umani," Rome, Italy, November 17, 2003.
  • "Lo sviluppo sostenibile dell'etica sociale," paper delivered to the Second World Forum on North and South, Rome, Italy, October 23, 2003.
  • "Perché una dottrina sociale della Chiesa?", paper delivered to the 21st international meeting of theologians for the permanent formation of the clergy organized by the Pontifical Congregation for the Clergy, Rome, Italy, September 29, 2003.
  • "The Catholic Human Rights Tradition: Francisco de Vitoria and the Salamancan School," paper delivered to the annual meeting of the American Political Science Association, Philadelphia, Pennsylvania, August 31, 2003.
  • "The Christian Roots of Europe," meeting of European youth with politicians, Rome, Italy, January 25, 2003.
  • "La dignidad de la persona humana como fundamento de los derechos del hombre y principio rector del bien común," international meeting of Ecristians, Barcelona, Spain, December 6, 2002.
  • "Il tacchino di ieri sera ed i diritti degli animali," Rome, Italy, November 29, 2002.
  • "Human Cloning and the Law," paper delivered to members of the New York State Bar Association, Rome, October 17, 2002.
  • "The Contemporary Relevance of Catholic Social Teaching," paper delivered to international meeting of priests, Rome, Italy, June 27, 2002.
  • "The Specificity of the Various Ecclesial Vocations," paper delivered to an international group of Christian businesspeople, Boncourt, Switzerland, March 1, 2002.
  • "The Church Since the Second Vatican Council," paper delivered to an international group of Christian businesspeople, Boncourt, Switzerland, February 28, 2002.
  • "The Contribution of Veritatis Splendor to the Development of Catholic Moral Theology," paper delivered for the conference Pope John Paul II and the Christian Proposal in the 21st Century, Rome, February 22, 2002.
  • "La teoria della guerra giusta e le sue applicazioni attuali," Rome, Italy, January 21, 2002.
  • "La Centesimus Annus dopo 10 anni," Verona, Italy, March 16, 2001.
  • "The State of the Church in the United States: Antecedents and Perspectives," Laguna Niguel, California, February 23, 2000.
  • "Ethics of Duty and Ethics of Responsibility," Rome, July 24, 1999.
  • "El depositum fidei, defensa de la fe y disenso," Rome, February 1, 1998.