This conclusion presents some closing thoughts on the key concepts discussed in the preceding chapters of this book. The book complements many quantitative modelling and other technical works showing the plausibility of high sustainable energy penetrations at the state, national, regional, and global levels. With technological strategies already addressed robustly by others, this book provides the non-technical approaches on state-led mobilisation for rapid GHG emissions reduction. The book contributes to sociotechnical transition scholarship as one of a few to envision a transition in the context of a challenging timeframe and rate of mitigation. It discusses Gedanken experiment through a thinking-aloud protocol in envisaging a qualitative scenario where the state re-assumes its original purpose: to protect citizens against harm. The book shows that generic strategies for mobilising finance and labour for rapid mitigation are attainable. It focuses on nation-states and multiple levels: states or provinces, cities or municipalities, and local communities.