I examine the question whether state consciousness is efficacious in the context of a more fundamental problem for mental causation known as "causal exclusion." Essentially, the generally accepted notion that physical events are part of a causally closed system entails that every neural event has a sufficient physical cause. So, barring overdetermination, mental events are unable to cause neural events. This result is a step in Jaegwon Kim's Causal Exclusion Argument (CEA). I argue that CEA poses a problem for conscious causation, and furthermore that proposed solutions to it do not necessarily secure the efficacy of state consciousness.