Is it a barrage? Or a fusillade? A torrent, sweeping and unprecedented? Or is it bold, urgent, transformative and necessary? Pundits on either side of the US’s polarised political divide are running out of words to describe the impact and scale of Trump’s executive orders since he took office just a few weeks ago. But from scientists’ perspective – and not just those losing their jobs and funding – it’s hard to even find one that can convey their sense of utter shock, exhaustion and dismay.

It’s a lot to take in. At the Munich Security Conference in February, European leaders were also shocked to be told by the US secretary of defence Pete Hegseth that the US would no longer be focused on European security. Faced with what would once have been an unthinkable scenario, those same leaders resolved to strengthen their support for one another and make new compacts for their security. The science community faces a similar realisation that former certainties and assumptions may no longer be valid, and it must also be ready to speak up for itself.

Decades of sustained support for science have been a tacit endorsement of its role as a societal good

The full details of these changes are explored in our coverage, but they include eliminating diversity, equity and inclusion initiatives and banning mention of climate change, along with huge cuts to research grants from federal funding agencies and the dismissal of thousands of staff at those agencies in the name of efficiency. This is hardly the first time a president has promised a streamlined government, but the Department of Government Efficiency led by Elon Musk has simply taken an axe to that Gordian knot. Many of those affected by the cuts are early career researchers, raising the prospect of a lost generation of scientists.

Former Trump science adviser Kelvin Droegemeier has said that Trump’s rollback of regulations offers opportunities to ‘unleash … our intellectual capacity’ but the other experts we’ve spoken to all find it impossible to see how the net effect of such deep and rapid cuts and layoffs can be anything other than immense harm. These are changes with far-reaching consequences that go well beyond the US. Decades of sustained support for science are part of what gave the US its world-leading position, and has been a tacit endorsement of science’s role as a societal good.

In response, the science community must speak up and keep making the case for science. There is an abundance of evidence that shows consistent state investment in R&D benefits society at large through better public health and economic growth. And there is a sound business case for diversity initiatives, such as the management consultancy McKinsey’s research showing a correlation between boardroom diversity and better company performance. Decarbonising the economy is our best hope for addressing the causes of climate change and avoiding its catastrophic effects.

Even well-established facts, such as vaccines being safe and effective, may need to be defended. The US Department of Health and Human Services is now being led by the vaccine critic Robert F Kennedy Jr. As the chief executive for the American Association for the Advancement of Science, Sudip Parikh, said recently, Kennedy ‘is not the right person to lead the HHS … because curing disease, addressing health, requires a search for truth, requires science’. Nevertheless, Kennedy holds that position, and so scientists everywhere must be prepared and armed with the evidence.

Unfortunately, many of these issues have now become heavily politicised. That means arguments for science must be made on the basis of its strengths, on evidence and rationality, so that those arguing in bad faith cannot abuse science as a political football. That science has made the world a better place, and will do so again, is not a political statement.