Anti-Brexit protesters are seen outside the Houses of Parliament in London on January 29, 2019.Henry Nicholls / Reuters

From the point of view of those outside Britain, Brexit must look like a mess. And how it looks is how it is. A mess. As a longtime Labour Party politician and a member of Parliament since 2010, I believe the only way out is through another referendum.

Now, I can imagine that people might wonder, having had our politics turned upside down by a ballot measure, why anyone would think another one is wise. The reason is that the 2016 Leave campaign was inherently contradictory. Brexiteers argued that by voting to sever itself from the European Union, Britain could retreat from the world’s challenges. Yet they also promised that Britain, on its own, could be a world-leading power and economy.

For some on the right of British politics, the answer to the world’s challenges is Donald Trump–style isolationism and protectionism. The Leave campaign exploited the refugee crisis to drum up fears of mass migration to the United Kingdom. The leading Brexiteer and former Foreign Secretary Boris Johnson claimed that Turkey would soon join the EU, implying that Brexit was necessary to spare the country of the need or responsibility to welcome new citizens of Turkish origin. And that familiar strain of anti-immigrant rhetoric could be heard throughout the campaign.

Brexiteers foretold a quick expansion in British industries protected from European competition and European trouble. They suggested, for example, that leaving the EU would free Britain’s waters from European trawlers and that the British fishing industry would boom as a result. Matthew Elliott, Vote Leave’s chief executive, said Brexit would put the U.K. in a uniquely good position for negotiating trade deals. In July 2016, former Brexit Secretary David Davis said new trade agreements “will come into force at the point of exit and they will be fully negotiated.” This could not be further from the truth. Two and a half years on, the U.K. is no closer to an independent trade deal with anyone.

Brexit, as described to the people who voted for it, was supposed to turn the U.K. into a commanding global player by removing it from the global stage. That’s incoherent. And that is why Prime Minister Theresa May is having such a hard time enacting it.

The proposal she put before Parliament in January was a complete muddle, and it was voted down by a resounding majority of 230. It did not resolve central questions on trade, immigration, or the nature of the U.K.’s future political relationship with the EU.

This week, the Conservatives managed to pass an amendment, giving the illusion of a united party, that instructed May to renegotiate her deal with the EU. She is supposed to focus on how the border with Ireland will work when the U.K. leaves the union. But a renegotiated deal is a unicorn—it is not going to happen. Europe and the prime minister have said as much. Again and again. The liberal wing of the Conservative Party wants to protect rights and jobs, while its hard right wants to fully escape the EU. May will never succeed in pleasing both sides.

This, then, is the reason for contemplating another referendum. In 2016, no one knew how much Brexit would cost. No one knew that this internal contradiction—that Britain would close and open up to the world at the same time—would produce such a catastrophic car crash. No one can say what it will mean for our population, which is aging like most in the developed world, to suddenly stop the free movement of European citizens into our country. Most likely, the country will struggle to staff many of its most important businesses and public services.

The lack of clarity means that the public should have a say in how to move forward. We have to have this out, properly. Under any normal circumstances, the country would be having a general election now, but the will of the Conservatives to keep their hands on the tiller of power, without any real direction, prevents that outcome.

The truth is that the 2016 campaign was terrible on both sides. The argument for continued membership in the EU was that Britain would be worse off without it. True enough, as has been shown by the economic reaction since the vote, but utterly uncompelling, given the next-to-zero wage growth experienced by huge sections of the population from the 2008 crash onward. What’s more, austerity fiscal policies pulled the rug out from under many communities. People felt that they were being asked to vote to protect a status quo that was not working for them.

A second public vote is not at all impossible. Recent opinion polls have shown that a majority of the population wants another referendum, and parliamentarians across the House of Commons support that option, as well. We will vote on the prime minister’s deal again in a couple of weeks. In all likelihood, it will fall again. Where do we go from there? A public vote is the only way out.

A new Remain campaign would not privilege the already privileged. It would begin with listening and deliberation, and would include institutions such as faith groups and trade unions that have been crying out to be more involved. The best argument for the European Union is the solidarity it offers. It is not faultless, but the risks of globalization, new technology, and an ever-changing economy are surely better managed in tandem with others.

Nationalism in Europe means power for the already powerful. Solidarity pushes back the other way. That is the argument my party must make in another referendum, and we must make it clearly.

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