There is a saying in the halls of British political power that scientific advisers should be “on tap, not on top”. This pithy aphorism, often attributed to Winston Churchill, highlights that, in a democracy, science should guide – not dictate – policy-makers’ decisions. Never was this truer than at the height of the covid-19 pandemic. Despite politicians in the UK claiming to “follow the science”, there were many decisions – from paying people to self-isolate to closing schools – that couldn’t be made on scientific advice alone. What’s more, some questions couldn’t immediately be answered by scientists. Policy-makers were forced to muddle through. By contrast, the Trump administration is now turning off the scientific taps, as government health bodies overturn long-established guidelines on everything from vaccines to cell phone radiation, all in the name of the “Make America Healthy Again” movement. “ By mid-2027, we should have much stronger evidence on social media harms “ But what about situations where the science is still evolving, and we don’t face a global emergency? The question, then, …