The battle for Brexit is so much bigger than the issue of Britain's membership of the European Union. And it's certainly bigger than the 40-year internal struggle within the Conservative Party.

What becomes painfully obvious after the referendum, if not before, is that this is a struggle over what kind of country we want to be – and no doubt what kind of world we want to shape.

It's partly an old battle over the economic model: concerns about the distribution of income and wealth in the real world, which are associated with growing mistrust of big money and business.

But it's much more It's about identity and culture. Surveys now show many people who are willing to make economic sacrifices if they can find a better sense of control over their lives and their communities.

This national populism has become alarmingly global – as these trends that infect Great Britain are widespread, from Trump to Brazilian Bolsonaro, from Hungarian Orban to Italian Salvini. Such political shifts can not be rejected as temporary deviations.

For liberals – whether you are a Liberal Democrat or liberal-minded – this struggle is particularly challenging. It could easily turn out to be an existential threat to the world that we thought would be laboriously built. And pointing to the balancing of liberal victories – such as the election success of President Macron or Justin Trudeau – does not feel so comforting anymore.

The question is: how should I answer?

The rights have predictably responded by accepting the shift – be it a Brexit, an anti-immigration or the pretext that Britain can return to a glorious past. While the liberal and commercial traditions of modern conservatism are increasingly uncomfortable, few have had the self-confidence to resist the new populist nationalism of their party.

The answer of the left is equally confusing and unconvincing. The options range from a full embrace of state socialism to the revival of a social democracy that has not worked in the rest of Europe against this populist attack. A runaway run by Tom Watson may be more convincing than the independent group, but so far the Labor Party has been struggling even more than the Tories to respond.

Not that the liberals would have done better. While the Liberal Democrats have identified the "big problems" of the last 15 years – from Iraq to Brexit – as correct, we have withdrawn the popular support. Weakened in the electoral area, Liberal Democrats and Liberals still do not need to develop a convincing strategy internationally.

But one thing is certainly possible. Liberalism was the most consistent political philosophy of the modern age and does not go away.

To get back into the game, we must recognize that the divisions of Brexit and the rise of national populism have existed for decades. Education departments where too many children have no equal opportunities in life. Economic divisions in which poverty through poverty lets families forget and leave behind. Political divisions in which the London powers are not interested in the rest of the country.

And we must have the honesty to play our part in not dealing with such long-standing divisions. For example, in immigration, we must recognize that governments have undermined the willingness of some to accept legal immigration by not engaging in illegal immigration.

Finally, we must recognize the challenge of political dialogue in the age of Twitter, Facebook and false news. Reasonable debates are no longer in fashion. Proofs and experts are dirty words. Cooperation and compromises are considered weak. In other words, the traditional weapons of liberalism have been dulled.

Paradoxically, I have the impression that only liberalism is in a position to repress this illiberal flood.

If we can improve our instinctive optimism and hope in a way that solves people's fears, we can successfully defend progress – and take it to another level.

The opportunity must be at the heart – with training and training. However, this age-old liberal offer must go hand in hand with enormous resources and a tireless focus on the children, adolescents and adults currently receiving the worst offer. And above all, we need education that involves young people who are interested in their hopes and aspirations and not in the prejudices of the young Daily Telegraph and Michael Gove.

And liberals have to accept the emotions of the voters. Why did Remain fight the referendum for reason only when it was clear that Leave had no such intention? Why did not Remain even try to make an argument for stopping wars? If we give the populists the monopoly of caring, we lose.

Above all, we need to describe another economic and political model – where people know that they are valued and listened to.

Liberal thinking flooded with practical options – and many political leaders around the world are experimenting. From facilitating common models in our utilities, from energy to railways, to helping local populations to make an informed decision, not just theirs. From the taxation of land and not from income through electoral reform to the reconstruction of local democracy.

I think an environmental agenda should not be dismissed as an obsession with the middle class, as it is important for the health and employment agenda.

From air pollution to sustainable, high quality food, a comprehensive green health agenda could be very popular.

Liberal Democrats can already point to thousands of jobs created by our renewable energy policy – not least the UK's global leadership in offshore wind turbines and new factories in places like Hull and Grimsby.

The challenge now is to accelerate action against climate change through the reform of the City of London and the entire financial sector in the UK. If we force them legally to consider climate risk, we can create unprecedented levels of green investment in the UK.

If liberal ideas can again reach all parts of our country – if they offer solutions for departments and can hope for disenchanted ones – we can once again become an open, tolerant and united country.

Ed Davey is a Liberal Democrat spokesman on internal affairs and a deputy for Kingston and Surbiton.