Butler formerly served as the director of the Judicial Education Program at the American Enterprise Institute-Brookings Institution Joint Center for Regulatory Studies.
He has acted as an expert witness in a legal cases involving antitrust, restrictive covenants, damages, joint ventures, and other issues.
Butler ran unsuccessfully as a Republican for the U.S. House of Representatives for Virginia's 11th congressional district in 1992; he lost the general election to Democrat Leslie L. Byrne.
After 1992 Butler Fred C. and Mary R. Koch Distinguished Professor of Law and Economics at the University of Kansas School of Law and School of Business, and for a short time served as dean of the Chapman University, Argyros School of Business and Economics and chairman of the Chapman University Law and Organizational Economics Center before moving to Chapman in 2001.
[5] After he yielded the deanship to Ken Randall, Butler assumed the Henry G. Manne Chair in Law and Economics.