As director of Cato's health and welfare studies, Michael Tanner heads research on new, market-based approaches to health, welfare and Social Security. Under Tanner's direction, Cato launched the Project on Social Security Choice, which is widely considered the leading impetus for transforming the soon-to-be-bankrupt system into a private savings program. Time Magazine calls Tanner, "one of the architects of the private accounts movement," and Congressional Quarterly named him one of the nation's five most influential experts on Social Security.

His most recent book, Leviathan on the Right: How Big-Government Conservatism Brought Down the Republican Revolution (2007), chronicles the demise of the Republican party as it has shifted away from its limited government roots. His other books include, Healthy Competition: What's Holding Back Health Care and How to Free It (2005), The Poverty of Welfare: Helping Others in Civil Society (2003), and A New Deal for Social Security (1998).