James M. Buchanan won the 1986 Nobel Memorial Prize in Economic Sciences for developing the contractual and constitutional bases for the theory of economic and political decision-making.
Buchanan was a leading figure in public choice theory, which applies economic analysis to politics and government institutions. He examined how voters, politicians, and public officials make choices under rules, and he emphasized the importance of the constitutional framework governing those choices. His approach treated political actors as decision-makers rather than assuming that government automatically acts as a benevolent planner.
The prize recognized Buchanan alone in 1986. His work is often discussed alongside public finance, voting rules, and constitutional economics. Amartya Sen won in 1998 for welfare economics, Gary Becker in 1992 for economic approaches to human behavior, and Douglass North shared the 1993 prize for economic history.