UK Conservative Prime Minister Theresa May’s triggering of Article 50, officially beginning Britain’s exit from the European Union, is a watershed moment. Britain has become the first state to ever begin the process of leaving the EU.

Brexit is one expression of centrifugal forces tearing apart the European Union, revealing the failure of all attempts to overcome, within the framework of the capitalist system, the national antagonisms that gave rise to two world wars in the 20th century.

The consequences of Brexit pose grave dangers, not only for the British working class, but for workers and young people throughout Europe. Behind May’s rhetoric about acting “in accordance with the wishes of the British People,” the Tories are intent on waging an intensified offensive against jobs, wages, working conditions and essential services. The aim is to complete what they describe as the “Thatcher revolution,” involving the removal of all restrictions on business in what the Daily Telegraph declared a “bonfire of EU red tape.”

The employment and residency status of hundreds of thousands of EU citizens in the UK and of British citizens in Europe is threatened, while they are cynically used as bargaining chips in negotiations over the multi-billion euro Brexit “divorce settlement.”

Across Europe, Brexit has strengthened right-wing forces such as the National Front in France, heightening the danger of Europe’s disintegration into competing nationalisms. The nationalist and xenophobic sentiments whipped up by Brexit even raise the possible break-up of the UK, with the Scottish National Party demanding a second independence referendum and Sinn Fein and the major parties in the Republic of Ireland raising a possible “border referendum” on unification.

The wave of nationalist reaction expressed and encouraged by Brexit has found its most malignant expression in the presidential victory of Donald Trump, who described his own protectionist “America First” agenda as “Brexit plus, plus, plus.” Trump has sought an alliance with May’s government and Europe’s far-right in order to encourage the break-up of the EU and the weakening of Germany as an economic rival of the US.

This explosion of national and inter-imperialist antagonisms, which the post-1945 unification of Europe supposedly relegated to a dark past, once again raises the threat of a descent into war. Writing in the Financial Times, Martin Wolf, warning of the consequences of Brexit for Britain’s bourgeoisie, wrote: “Only someone ignorant of history would dream that Europe would be more prosperous, stable, influential, democratic and liberal if the EU shattered into 28 national pieces. The system of nation states has repeatedly proved unstable. In this case, with the US increasingly withdrawn, the EU’s collapse might lead to a struggle for hegemony between Germany and Russia or, worse, a pact between them at the expense of weaker neighbours.”

These events are a devastating political indictment of those pseudo-left groups such as the Socialist Party and Socialist Workers Party, who advocated a “Left Leave” vote and who continue to put a “left spin” on the anti-EU message of the Tory right. However, those who advocated a Remain vote as the basis for opposing these right-wing developments are equally culpable in the outcome.

It has become commonplace for those in the UK who oppose Brexit to denounce the millions of workers who voted Leave for their supposed “ignorance” and stupidity, who supposedly voted out of agreement with the anti-immigrant xenophobia of the UK Independence Party. From this flows the inevitable conclusion that the working class is also responsible for the rise of Le Pen, Trump, et al.

This turns political reality on its head. It was the apologia for the EU offered up by the Remain campaign that drove sections of more oppressed workers into the clutches of the nationalist right.

Aside from a few token references to the need for “reform”, the Remain forces avoided all criticism of the EU and waged a campaign that appealed almost exclusively to big business and to the social concerns of a section of the professional middle class. They were oblivious to the anger generated among workers by years of austerity, poverty and social misery. They were all too ready to excuse the role played by the EU in imposing equally devastating attacks throughout Europe.

In addition, they advanced as Remain’s leadership an alliance of Prime Minister David Cameron’s Tories with the Labour Party and the Trades Union Congress. For decades, the Labour Party has embraced policies of austerity and war, while the trade unions have betrayed every struggle mounted by working people.

Brexit demonstrates above all that it is the rotten pro-capitalist politics of Labour and the trade unions, and of their equivalents internationally, that have handed the political initiative to the right-wing. Indeed, the most devastating indictment of the pro-EU politics of the Remain campaign was the role played by Brussels in the destruction of Greece’s economy and the pauperisation of its workers.

Just one year before the Brexit referendum, the Greek working class handed the pseudo-left Syriza government a massive referendum vote to oppose EU-dictated austerity—only to see that mandate betrayed within days by Prime Minister Alexis Tsipras on the basis of ensuring Greece’s continued membership in the EU.

More fundamental still, the framework in which the referendum was fought was conditioned by the decades-long repudiation of socialism by the parties that once claimed to speak for the working class.

The essential claim of the Remain campaign is that the EU continues to represent a guarantor of European unification and a bastion of progress against nationalism and war.

Trotsky’s description of such claims as a “Utopia” has been fully vindicated. He explained in 1917, “The democratic republican unification of Europe, a union really capable of guaranteeing the freedom of national development, is possible only on the road of a revolutionary struggle against militarist, imperialist, dynastic centralism, by means of uprisings in individual countries, with the subsequent merger of these upheavals into a general European revolution.”

This appraisal has been confirmed by the contemporary fate of the EU.

In its statement, “For an active boycott of the Brexit referendum!” the Socialist Equality Party explained, “The EU is breaking apart and cannot be revived... unity within the framework of capitalism could never mean anything other than the domination of the most powerful nations and corporations over the continent and its peoples. Rather than national and social antagonisms being alleviated, they have taken on malignant forms.”

The SEP called on workers and young people to carry out an active boycott of the referendum because the Remain and Leave campaigns were both headed by sections of the ruling class “that stand for greater austerity, brutal anti-immigrant measures and the destruction of workers’ rights.”

We called for the working class to advance “its own internationalist programme to unify the struggles of workers throughout Europe in defence of living standards and democratic rights. The alternative for workers to the Europe of the transnational corporations is the struggle for the United Socialist States of Europe.”

By advancing a clear political opposition to all factions of the ruling class, the SEP set out to prepare the way for the development of an independent political struggle of the British working class, which could only be taken forward “as part of a continent-wide counteroffensive by the working class.”

The socialist and international perspective fought for by the SEP, in alliance with our European and international co-thinkers, today offers the only antidote to the nationalist poison seeping into Europe’s pores.