Few things about British political culture are as characteristic and as demeaning as the collective cringe before the United States. The cringe takes many forms. It ranges from the inflated preoccupation with the “special” relationship at the very summit of British government to the risible lack of self-awareness that leads many Westminster spear-carriers to cultivate Mastermind levels of knowledge about TV series such as The West Wing and House of Cards.

These impulses do not merely acknowledge the US’s importance. They bend the knee to it. Deep down, they seem to express a post-imperial British craving for some of the US’s reflected greatness. You might even say that, mentally at least, Britain already is a vassal state, only not of the European Union but of the US.

This week’s midterm elections have been a reminder of the many ways in which this cultural cringe affects journalists and broadcasters. As Tuesday turned into Wednesday, we all seemed to be either taking part in the midterm coverage or glued to it. Natural enough, in one sense. But there is something collectively dysfunctional about a British political culture whose participants obsess about the Texas Senate race or the Kansas governorship at the same time as most of them would struggle to name the prime minister of France.

This is not to argue that the 2018 midterms are not important. Nor is it to be in denial about my own inner anorak – yes, I like American elections too. But the British political class’s wide-eyed appetite for Americana should be challenged. If it devoted even a small amount of that kind of attention to politics in countries nearer to home that directly affect Britain’s future in ways that Kansas never will it would be a lot more persuasive.

Britain’s fanclub approach to US politics gets in the way of efforts to reflect on the wider meaning of these midterms. It is important for Americans that the Democrats have regained control of the House of Representatives this week. Their victory brings some of the checks and balances of the US constitution back into play against Donald Trump. The Democrats now get a more decisive say on the federal budget. They will use Congress’s subpoena and scrutiny powers to make the president’s life tougher. If and when the special counsel, Robert Mueller, is allowed to publish his report, they will not brush his findings under the carpet.

These are significant events. But they do not directly affect us or our interests. For Europeans, what should matter about Tuesday’s elections is that none of the big things about the role of Trump’s America in the world is likely to change. In fact, these results suggest strongly that the Trump foreign policy revolution will deepen and become increasingly entrenched, and even permanent. Trump was not routed this week. He is more likely than ever to win a second term, especially if the Democrats are divided.

These midterms therefore tell the rest of the world something very important. They tell us that America First is not going away, that it is on course to be the new normal, that it is not some unfortunate aberration that can be reset to the status quo ante of 2016. The midterms strongly suggest that the next two, and quite probably six, years of American international policy will be a continuation, perhaps more forcefully, of the last two. Moreover, there is no guarantee that any new administration coming into office in 2024 will be in a position to significantly rebuild the destruction left by the Trumpian international legacy.

For Europeans this means facing up to a historic readjustment. The world and the Europe that were initiated by the armistice of November 1918 is coming to an end. From that date onwards, the power, interests and sympathies of the US could be relied upon to come to Europe’s military and financial rescue in hard times and, later, to guarantee its peace and prosperity through multilateral political, trading and financial institutions. No longer. Perhaps never again. Today, Trump’s policy of America First means that those shared values and institutions have run their course. The US’s relations with the rest of the world are to be transactional. Take it or leave it.

It follows that the very notion of a transatlantic worldview, dedicated to maintaining the peace, the nations, cultures, peoples and values of Europe is ending too. It means that Europe and its nation states could one day find themselves with no natural allies and that the defence and projection of European interests is now a matter for which, with the rise of China, in the face of Russian provocations and under pressure from migration and instability from the south, Europeans alone must take responsibility. America First is making Europe First inevitable.

The midterms ought to provide a reality check of a similar order for the UK. The US’s failure to repudiate Trumpism this week could hardly come at a more serious moment for this country. It leaves Brexit Britain in danger of becoming the vassal not just of an idea, but of a global disruptor. There is very little time left to grasp that it will not be in our interest in any way to collude in a tectonic change to the international order that is being driven by American domestic politics.

We delude ourselves if we think we are essential to this new American unilateralism. It is a fantasy to suppose we can moderate America First by the old foreign office tactic of hugging the American establishment close. Washington does not work like that any more. Britain must look elsewhere for its allies now. The place to find them is obvious. Whether we like it or not, we are always going to be what geography and history have made us – a significant part of Europe. Brexit was always a dangerous folly on any terms. To persist with it now may soon seem almost suicidal.

A century ago the guns finally fell silent in France. For the past seven decades we have lived in a better and safer world that had learned some of the hard lessons about mass warfare and immiseration. Today we are once again not safe, though in a new way. Trump is not merely neither our friend or ally. He is working to restore a global order of competing sovereign powers. He has no interest in our shared security. Neither European prosperity nor peace – including peace in Ireland – have meaning for him. He has a positive interest in imposing an unequal trade deal on any British government that comes asking for one. He is already our rival and potentially something worse. Now he may be there for the long term. In the US this week, nothing much changed. In Europe, as a result, everything has.

• Martin Kettle is a Guardian columnist