The Socialist Party, publishers of Socialism Today, campaigned for a Leave vote in the June 2016 EU referendum.
The European Union is a bosses' club, at bottom an institutionalisation of a series of treaties agreed between the capitalist classes of the different member states.
Socialists, and the working-class movement as a whole, should never offer one ounce of support to the capitalists' rule of society, in general and in particulars.
Even if there had been no other considerations involved, given the binary choice presented in the referendum, the Socialist Party would have refused to give a vote of confidence to the capitalist EU.
But we also supported a Leave vote in 2016 because of the impact we predicted it would have on the Tory Party.
We pointed out in advance that a Leave victory would unseat David Cameron, as it did within hours. We argued it would push the Tories ever closer to a split, similar to the 19th century schisms over the Corn Laws and Tariff Reform, opening the way for a Jeremy Corbyn-led government.
That perspective was mocked at the time by many on the left. Just before the poll, the Guardian columnist Paul Mason, for example, scoffed at those "fantasising that if Leave wins Cameron will fall". (21 June 2016) Now the fragmentation of the Tory Party and the prospect of sweeping political realignments is the new accepted wisdom.
This situation creates opportunities but also, with the Blairite fifth column within the Labour Party on Brexit manoeuvres, dangers too.
The need for the workers' movement to have an independent class position on the EU and a socialist, internationalist programme has never been greater.
The EU is a bosses' club and the Tories are the oldest bosses' party in the world. So why are they facing potential existential divisions over Brexit?
No individual business executive, police chief, judge, journalist or state official is directly and immediately representative of capitalism as a whole, however much they defend it.
Capitalist politicians too, needing to ideologically justify a system based on the exploitation of the majority by a small minority, can also adopt positions against its overall interests in order to nurture a social base.
When Jacob Rees-Mogg spoke at the House of Commons Brexit select committee earlier this year against a 'transition arrangement' with the EU - saying it would turn Britain into a "vassal state" - his audience was the 100,000 or so Tory Party members, not the broad majority of Britain's ruling class.
Yet Rees-Mogg and his European Research Group of Tory MPs, with its own WhatsApp group parliamentary whip, are in a pivotal position.
Karl Marx and Friedrich Engels in The Communist Manifesto famously described capitalist governments, "the executive of the modern state", as committees "for managing the common affairs of the whole bourgeoisie".
Particularly in times of economic growth, conflicting material interests and ideological stances can be smoothed over. But sometimes the contradictions are too acute. That is the position the Tory government finds itself in today.
It is trying to deal with the most profound change in British capitalism's international relations since 1945 against the backdrop of a world economy and political firmament still shaped by the financial crash of 2007-08 (see the article by Judy Beishon, Ten Years Since the Crash, on page ten).
The Tories' unfolding implosion was excruciatingly illustrated in the contortions last month on the issue of a post-Brexit customs union with the EU.
Speaking during her China visit Theresa May initially refused to rule this out. The home secretary, Amber Rudd, a Remainer in the referendum, then said on the Andrew Marr show that it was a possibility.
Literally minutes later, the housing minister Dominic Raab, a 2016 Brexiteer, openly contradicted her. No.10 was then forced to issue a statement denying it was policy to be in "the customs union" or even "a customs union" - but not saying what the policy was.
No wonder the British Chambers of Commerce (BCC), representing 75,000 firms, issued an Open Letter to the Prime Minister pleading for "those elected to govern to make choices", to provide "answers to the many practical questions businesses now face"!
The BCC's anguish reflects a growing fear among the British ruling class as Brexit day looms. The EU's free trade deals with 53 countries cannot be simply inherited - not least because they will want to know what Britain's future trade relations with the EU will be.
The tariff, quota, trade preferences and subsidy rules lodged with the World Trade Organisation (WTO) by the EU also cannot be simply transferred to Britain which, after it has divided them up with its EU ex-partners - not necessarily amicably - will then need to get them approved by all the 163 other WTO members.
And tariffs are less significant than non-tariff barriers, such as regulations, especially for services which make up 80% of the British economy.
Financial and ancillary services, for example, which depend on 'passporting' rights under the EU single market to conduct business across the 28 member states, employ 730,000 people.
Roughly 7% of global foreign direct investment, some £1 trillion involving 500 multinationals, has been made in Britain predicated on its participation in the customs union and the 500 million-consumer EU single market.
On a capitalist basis the 'economically logical' position would clearly be for a 'soft Brexit' or Bino, Brexit in name only.
But it is not even guaranteed that there will not be a 'no deal' crash-out exit. Capitalism is a system of political economy, not economics alone.
The workers' movement must maintain an independent class opposition to a Tory Brexit, 'soft', 'hard' or 'no deal'. But that is not the position of the Blairite defenders of capitalism within the Labour Party.
The Guardian journalist Martin Kettle reported the fury of right-wing Labour MPs at Jeremy Corbyn's statement at the start of 2018 that Britain could not remain in the single market. "But Corbyn's remark might not be as portentous as that suggests", he advised them (12 January). "The real issue is the future relationship with the single market, the customs union and other European regulatory agencies and enforcement systems", and Labour's position is still to be agreed.
The right-wing Labour shadow Brexit secretary Keir Starmer has made the same point. "What underpins access to the single market and customs union is a level playing field", he said in an Andrew Marr interview. (The Guardian, 11 December 2017) "You have to stay on the same level playing field. The Labour Party doesn't have a problem with that".
Which Labour Party? The EU 'playing field', for example, requires public procurement contracts - a £240 billion annual spend in Britain - to be put out to competitive tender to firms across the EU if they are worth over £120,000.
Jeremy Corbyn, calling for an end to the 'outsourcing racket' after the collapse of Carillion, rightly pointed out that single market rules would "potentially make it harder" to do so.
That approach needs to be generalised. The most important 'Brexit policy' Jeremy Corbyn could adopt now would be to declare that a government he leads would take whatever decisive socialist measures are necessary in defence of the working class regardless of EU treaty provisions and regulations.
The majority of EU regulations - on standardisation, consumer protection, environmental safeguards, workplace rights and so on - are unobjectionable.
However, those that would create distracting legal obstacles - the state aid rules, procurement laws, the posted workers' directive, etc - should be declared null and void.
That holds even though they could not stop a Corbyn-led government supported by a mass movement from carrying out socialist policies.
A bold stand by Jeremy Corbyn against the anti-working class treaties and policies of the EU could electrify the debate across Europe.
A call to scrap the austerity-driving European Fiscal Compact, write-off the eurozone debts, and to create a 'level field' based on public ownership of the banks and major monopolies in each EU country, could mobilise workers continent-wide and prepare for a new collaboration of the peoples of Europe on a socialist basis.
The Tories' Brexit trauma, which will only deepen in the weeks and months ahead, is creating new opportunities for working-class politics.
The first step is a clear programme for a socialist and internationalist break with the EU bosses' club.