In general, however, the logic of collective action remains a troublesome problem. Even if relatively large numbers of individuals periodically do engage in collective action, public choice suggests that their commitment is likely to be highly unstable and active participation in the policy process rare. In a recent study of environmental interest groups in the UK, for example, Jordan & Maloney (1997) found that the vast majority of those registered with Friends of the Earth were essentially ‘passive’ members who rarely if ever became actively involved in individual campaigns or participatory events.