In the debate on strengthening the international financial architecture, which peaked in 2002 after a series of emerging market sovereign debt crises, the universal adoption of collective action clauses (CACs) was the most promising reform proposal. Academics and the official sector had been promoting CACs at least since 1995, yet market practice did not begin to change until 2003. This delay is often attributed to the opposition of investors and sovereign borrower to CACs. This paper evaluates the publicly stated as well as the suspected private motives of the two sides to block the spread of CACs. It draws on a wide range of existing evidence and adds some new theoretical considerations to show that there is no reason to be sceptical of C...