Q: Is it really worth voting on 23 June?

A: Yes. All polls suggest that, if “leave” wins, it will win because the embittered “why isn’t Britain the same as it was in the 1950s” types turn out in greater numbers than the more cosmopolitan-minded young.

Let “leave” win, and you lose your EU citizenship, which entitles you to travel, and to move for work, freely in Europe. You (and two million British citizens living in EU countries) may well lose arrangements like the European Health Insurance Card, which entitles you to free or heavily-discounted public health care across Europe.

Your friends and workmates and union colleagues who have come from other EU countries will find themselves stigmatised and in danger of expulsion. Workers will be divided. Ninety per cent of the workers from the EU already in Britain would lose their status here and have to apply for visas to remain, under what conditions no-one knows.

The people in Greece, Romania, Poland, Spain, Portugal, who could bring cultural enrichment and talent to Britain and flair to the British labour movement, as many of their country-people already have, will be excluded. Britain will become a meaner, more narrow-minded, country, maybe for decades into the future. All political debate will centre round just how malicious the new rules to block European migrants should be.

The still-very-limited conciliation in Ireland will be reversed when the border between North and South there, currently crossed every day by people to work or to shop or to visit, has to have Britain-EU frontier checks. A second Scottish separation referendum, and yet another border erected between Scotland and England, will be very likely.

Q: There’s nothing wrong about people wanting to come to Britain. But resources are stretched here. Too many migrants will overburden public services and force down pay rates, especially for the lower-paid.

A: Blocking migrants will overburden public services even more, since many services, like the NHS, depend heavily on migrant labour.

If new provision is not created in areas where population grows, it’s because of the government’s cuts, not because of migrants. It’s not because of lack of resources, but because the government chooses to funnel the resources to the rich.

Migrants contribute £2.5 billion more in tax than they claim in benefits. Generally, countries with more immigration are economically more dynamic and prosperous. If the labour movement organises the migrants, the movement becomes stronger, culturally richer, broader-horizoned.

A study by Christian Dustmann and Tommaso Frattini found that in Britain between 1997 and 2005 middle earners gained 1.5p an hour and upper earners 2p from the effects of immigration. They estimated wages of the worst-paid 5% as 0.7p an hour worse than they would have been without immigration. That 0.7p is tiny compared to the positive effects which can be won when workers of all origins unite to win a living wage — and tiny compared to the negative effect of dividing workers by country of origin.

Q: Quitting Fortress EU would allow Britain to admit more migrants from Asia and Africa, instead of just from Europe.

A: The EU’s response to the millions fleeing horrors in Syria, Eritrea, and other countries has been wretched. But Britain has been more mean-spirited than EU countries like Germany and Sweden, not less so. Britain’s closed door to refugees and migrants from Asia and Africa is decided by the British government, not the EU. It would break no EU rule for Britain to open that door. The “leave” campaigners — right-wing Tories, Ukip, the Daily Mail, the Daily Express — agitate against non-European migrants as well as European. One of their arguments has been that if Britain remains in the EU, then some of the Syrian and other refugees admitted by less mean-spirited EU countries could use EU freedom of movement to come to Britain.

Q: So it’s about migrant rights? And what else?

A: Nation-state borders formed in past centuries are too narrow for today’s capitalism, let alone for socialism. Economic and cultural life spilled across those borders long ago. To try to re-raise those old borders, and cram life back within them, will impoverish us.

A cosmopolitan voluntary union of many nations and peoples, with the lowest possible internal borders, is a better starting point for a fight for democratic control over (inevitably international) economic life, and for a civilisation based on solidarity.

Q: But the EU is capitalist! Neoliberal! Look what it has done to Greece.

A: Of course it is capitalist! Put 28 capitalist states together, and you get a capitalist union. That will be changed only by working-class struggle across the continent. The lower the borders, the better the conditions for that united working-class struggle.

The objection of the leading “leave” campaigners — of the people who will shape what “leave” means, if the vote goes their way on 23 June — is that the EU is too restrainedly capitalist and not neoliberal enough. As the EU has part-harmonised conditions across the continent, there has been some levelling-up. The EU leaders could not bust German and French workers down to the conditions of Poland or post-Franco Spain, but could afford some “levelling-up”. The ratio of the poorest country’s GDP per head to the EU-28 average has increased very slowly, but it has increased, from 0.35 in 1995 to 0.48 in 2011.

Although Britain has an income above the EU average, we have benefited from levelling-up in other areas. Measures like the Working Hours Directive and the Agency Workers Directive were implemented in Britain only thanks to EU pressure. “Vote Leave” leaders want to scrap them.

Q: All talk about changing the EU is empty. The fact is, labour movements exist country by country. For now, the way to win gains is for labour movements to be able to push their own governments, free of international constraints.

A: Leaving the EU will not free a government from the constraints of the multinational corporations and of the global financial markets. In fact, the size of the EU means that an effective concerted labour-movement push can sway governments to partial defiance of world-market pressure more easily than could a push in a single small country.

In the EU or out of the EU, to win real changes the labour movement must unite across borders. Syriza’s surge in Greece was never going to win radical demands unless it could evoke and then unite with a cross-Europe movement against austerity. The Syriza leaders made some efforts to do that in 2012.

They were far too weak. But if they had been stronger, they would have been helped, not hindered, by the fact of Greece being in the EU and the consequent logic of promoting a united movement on cross-EU demands.

Q: The EU is undemocratic. The unelected European Commission and the unelected European Central Bank impose their will on elected national governments.

A: They do. So do the unelected Bank of England and the unelected bosses of big business. The answer is to win democratic accountability, something along the lines sketched by Yanis Varoufakis for his Democracy in Europe Movement (DiEM), not to raise borders.

Q: If Britain stopped paying EU budget contributions, it could spend more on the NHS.

A: Former Tory prime minister John Major was pushed into increasing NHS spending, after Thatcher was ousted in 1990, by accumulated agitation against the NHS cuts which Thatcher had made in the 1980s. Probably he had a hard time with some of the right-wing, anti-EU Tories about that, and the resentment rankles.

But what he said on 5 June about the Brexit leaders was right: “Michael Gove wanted to privatise [the NHS], Boris [Johnson] wanted to charge people for using it and Iain Duncan Smith wanted a social insurance system. The NHS is about as safe with them as a pet hamster would be with a hungry python”.

Q: It’s difficult to see exactly what difference Brexit would make. But for sure a “leave” majority on 23 June would discredit David Cameron and sharpen the Tories’ divisions. We should vote “leave” to get rid of the Tories.

A: A “leave” vote might well topple Cameron, to replace him with Gove or Johnson at the head of a Tory government, maybe with an explicit alliance with Ukip. There is no way that it would lead directly to the victory of the pro-”remain” Labour Party.

Deciding our tactics by what is bad for Cameron is short-sighted. Chaos, rancour, confusion, in a situation where right-wing forces dominate the stage, as they do, brings demoralisation, atomisation, sectionalism, chauvinism, regression, not socialist advance.

Q: What should the left do if the majority on 23 June is for Brexit?

A: We’ll be on the back foot. But we should and can campaign to reduce the loss of workers’ rights and migrant rights to a minimum, and to maintain and increase labour-movement links across the new borders our exploiters will put up.