The question of what demands ecosocialists should put forward in response to the climate crisis is a pressing one. Robin Hahnel, in “An Open Letter to the Climate Justice Movement”, argues that the climate justice movement should demand a cap-and-trade policy, abandoning its traditional stance against carbon trading. To Hahnel, carbon trading is the most realistic way for society to make carbon emissions cuts in the necessary time frame, and, contrary to the arguments of activists, it can be done in a socially just way. Although I respect Hahnel as a sincere and principled radical, I find his argument troubling. I believe it is marred by a misunderstanding of activists’ arguments against carbon trading and, more fundamentally, a lack of attention to the dynamic of reform and revolution.