Natural law
A significant portion of Budziszewski's work focused on the natural law tradition. His understanding of the natural law is much indebted to that of Thomas Aquinas. In his book, "The Line Through the Heart", Budziszewski attempts to show us how the natural law continues to illuminate the ethical and political dimensions of human existence today despite our best efforts to ignore it. Natural law is a fact in that it is real, we know it, and we cannot change it. It is a theory because we can reflect on our pre-theoretical knowledge of the natural law and attempt to develop a systematic account of it. Finally, the natural law is a scandal, it angers us because it confronts us.