After the horrors of the Second World War and the Holocaust, the world united to say ‘never again’. Never again would any state be allowed to persecute a section of the population on the grounds of their religious beliefs, ethnic background or nationality. Never again would the rhetoric of discrimination and ‘othering’ which allows such persecution to prosper be allowed to gain a foothold in our societies. Never again would we allow the fundamental dignity of all human beings to be so completely eradicated as it had been by the Nazi regime.

Post-World War Two, we as Westerners have been fortunate enough to live in a world in which we have had ample opportunity to learn these lessons, and no excuse to forget them. They have been drilled into us through our education, through remembrance services and through a wealth of documentation of the horrors of the Second World War in the media and in cinema. To varying degrees, we have all been brought up with some understanding of the events which led to the systematic murder of several million Jews, as well as members of other minority groups and countless political opponents. We know the dangers of allowing a stigma against minority groups to fester and to be propagated by the state through claims which tend to be founded on lies, or ‘alternative facts’.

And yet, today, in the year of 2017, the question of just how far these lessons have truly been heeded appears more acute than ever. If the warning sirens were not already sounding during Donald Trump’s presidential campaign, they must be heard loud and clear now in the first weeks of his presidency. Never again must the world stand by and watch as one of its most powerful states descends towards the oppression of minority groups and the erosion of fundamental rights.

Many will say that Trump, quite clearly, is not Hitler. That he seeks only to do what is necessary to protect the interests of the United States. They will say, also, that the US constitution and separation of powers will prevent him from having much practical impact. These arguments hold no weight. The man in question holds the most powerful office in the world. His every word has a profound impact and he has more than enough influence to radically alter the lives of millions of people both within the USA and beyond. With the most powerful office comes the greatest responsibility. A duty to respect not only the US Constitution, but the equal rights of all human beings across the world as enshrined in international law since World War Two.

That Trump has shown such flagrant disregard for years of painstaking work following that conflict, for instance in guaranteeing basic rights to refugees and  prohibiting torture and other inhumane treatment, in just two weeks in office is simply mortifying. Rather than dismissing the prospect of Trump inflicting any more serious harm, and focusing on appeasement and trade deals, the rest of the world must now be at its most vigilant in order to protect the liberal values and the rights which so many gave their lives to earn us. We need only look at some of the images and stories from US airports over the weekend in order to see the very real effect that Trump is already having on people’s lives.

It was heartening to see so many Americans unite so swiftly in protest all over the country, and to see sweeping international condemnation of Trump’s latest executive order. This resolve must not lessen as such executive action and policies continue to be rolled out. Indeed, it must strengthen as we remember the values which unite so many of us against Donald Trump and his regime. We simply cannot allow him to undermine the progress made in human rights protection on a global scale in the last 70 years. He has the capacity to take us back to some very dark places. The threat is real.

* Dan Webster is a Lib Dem member and final-year law student at Durham University. He blogs on civil liberties here.