We present a simple theory of the quality (competence and honesty) of elected officials. Our theory offers three main insights. Low-quality citizens have a 'comparative advantage' in pursuing elective office, because their market wages are lower than those of high-quality citizens (competence), and/or because they reap higher returns from holding office (honesty). Hence, voters may find themselves supply constrained of high-quality candidates. Second, bad politicians generate negative externalities for good ones, making their rewards from office increasing in the average quality of office holders. This leads to multiple equilibria in quality. Third, incumbent policymakers can influence the rewards of future policymakers, leading to path dependence in quality: bad governments sow the seeds for more bad governments. © 2003 Published by Elsevier B.V.