Who should enforce laws or contracts: judges or regulators? Many Coasians, though not Coase himself, advocate judicial enforcement. We show that the incentives facing judges and regulators crucially shape this choice. We then compare the regulation of financial markets in Poland and the Czech Republic in the 1990s. In Poland, strict enforcement of the securities law by a highly motivated regulator was associated with a rapidly developing stock market. In the Czech Republic, hands-off regulation was associated with a moribund stock market.