The rapid rise of social protection up the development policy agenda has been startling: it can achieve bigger development objectives, such as economic growth and the MDGs. Its predecessor 'social safety nets' was disparaged and attacked during the 1990s, and was then reborn as 'social protection' at the turn of the millennium.

The new agenda comes with a fresh array of conceptual frameworks, analytical tools, empirical evidence, national policy processes, heavyweight agencies and big names in development studies behind it. It is amenable to the 'right' and 'left', and prioritises moving people productive livelihoods. Advocates for social protection fall into two broad camps - the 'instrumentalists' and the 'activists'.

For instrumentalists social protection is about putting in place risk management mechanisms that will compensate for incomplete insurance (and other) markets, until poverty reduction and market deepening allow private insurance to play a more prominent role. Activists view the persistence of extreme poverty, inequality and vulnerability as symptoms of social injustice and structural inequity, and campaign for social protection as an inviolable right of citizenship.

These issues are debated in this IDS Bulletin. Commentators were encouraged to be provocative and pithy - and the protagonists are given a 'right to reply' to their critics. Some stirring encounters result. This overview highlights how rapidly thinking and practice have moved forward in a few short years, but it has also revealed that a range of conceptual, empirical and policy issues remain unresolved.