This book tackles a critical question. Why has the world struggled so much to coordinate policy to address climate change, despite political and scientific consensus? Despite landmark agreements and expanding knowledge, emissions have fallen unevenly and progress has repeatedly stalled or reversed. Democracy or Carbon Oligarchy? explains that failure by focusing on domestic politics: how institutions distribute power, how interest groups exploit “access points,” and why countries with similar wealth and technology diverge. Moving beyond arguments about mere political will, it situates energy and climate outcomes within the institutional architectures of industrialized oil super-producers: the United States, Canada, the United Kingdom, and Norway. Shum advances a neopluralist theory of climate politics, arguing that policy is shaped by the strategic capture of institutional venues by carbon-intensive interests. He shows how separation of powers, federalism, party systems, and electoral rules configure opportunities for a de facto carbon oligarchy. By mapping where binding decisions are made and who can reach them, the book offers a generalizable framework for diagnosing blockages, explaining cross-national variation, and identifying leverage points for sustaining ambitious climate policy over time.