The Washington Post has a long profile of National Security Adviser Tom Donilon, an alumnus of Catholic University. Donilon, whose brother is the communications director of the Archdiocese of Boston, may not be the highest-ranking Catholic in Washington, but he may be the most influential.
Donilon was a professor of mine in 1981 when he taught a course on presidential election politics. He is very smart, very comprehensive in his analysis of any given topic, deeply read as well as widely read (they are not the same thing) and super funny. As the article details, he also is pointing the country towards some of the long-term foreign policy challenges that were neglected woefully by the neo-cons in the Bush administration.