CJ112 Criminal justice cannot be successfully imposed from above, but needs as far as possible to be a product of a living, democratic community. The basic institutions of Green justice should be community-based and relatively informal in nature. They should provide maximum potential for public participation.
Just going through some of their policy documents, while their energy and transport policies look reasonable, their economic and military policies strike me as largely unrealistic.
(Update: Actually I should mention that I do disagree with a large section of the Energy document; I can't see any realistic way to drastically reduce CO2 emissions while simultaneously ceasing to use nuclear power. However, I think both are desirable goals.)