I grew up in a household where the anti-nuclear poster on the wall was as much a part of the political furniture as the trade union membership card on the mantelpiece. I understand the genealogy of this conviction — Chernobyl, Three Mile Island, the unsolved problem of nuclear waste, the associations with weapons programmes that have haunted civilian nuclear power since its inception. I am not dismissing the history. I am arguing that the history no longer justifies the position.

The arithmetic of decarbonisation is unforgiving. Solar and wind power have achieved cost curves that no one predicted fifteen years ago and are now the cheapest form of new electricity generation in most of the world. They are also intermittent, and the storage technology required to make an entirely renewables-based grid reliable at continental scale does not yet exist at the cost and capacity required. In the interim — which will last decades — something must provide the firm, dispatchable, low-carbon power that keeps hospitals, factories, and heating systems running when the wind does not blow and the sun does not shine. The realistic candidates are natural gas with carbon capture, which is expensive and unproven at scale, and nuclear, which is expensive and proven.

The countries that have retained and expanded nuclear capacity — France, which generates 70 percent of its electricity from nuclear plants; Finland, which opened Olkiluoto 3 in 2023; South Korea, which reversed its phase-out decision in 2022 — have lower grid emissions than comparable economies that have closed plants on ideological grounds. Germany's Energiewende, the most expensive energy transition in history, still produces more carbon per kilowatt-hour than France's largely nuclear grid at a fraction of the cost.

None of this means nuclear power is without problems. It is capital-intensive, politically contentious, and the waste management challenge, while technically manageable, remains politically unresolved in most democracies. But the question is not whether nuclear is perfect. The question is whether it is better than burning gas while we wait for storage technology that may arrive too late. On that question, I think the evidence is now unambiguous.

The progressive movement built its identity partly around opposition to nuclear power. It now needs to decide whether that identity is more important than the climate. I do not think it is. I suspect many people who share my political instincts agree, and are waiting for permission to say so out loud.