WHEN people wheel out the old quotation by Dean Acheson to the effect that Britain had lost an empire and not yet found a role, the rest of his speech is often forgotten. Acheson, who was President Truman’s secretary of state, went on to say that Britain’s attempt to play the part of a world power aloof from Europe by leveraging its “special relationship” with America was almost “played out”.

That was in 1962. More than 50 years later, those pushing for Britain to vote on June 23rd to leave the European Union are still in denial.

On April 22nd Barack Obama will be in London to tell people arguing for Brexit, as politely as he can, that they are mad, and that if Britain wants to retain much influence in the world, let alone a special relationship with America, it must stay in the EU. Jeremy Shapiro of the European Council on Foreign Relations, a think-tank, puts it starkly: “Britain can be a geopolitical actor within the EU or it can be a geopolitical irrelevance outside it.”

Mr Obama will not go that far, but last year he told the BBC that Britain’s place in the EU was a cornerstone of post-war peace and prosperity. He added: “We want to make sure that the United Kingdom continues to have that influence.” There is much at stake for America too if the British people choose not to listen.

For Mr Obama this is a farewell visit to an old ally and a chance to have lunch with the queen, who will just have celebrated her 90th birthday (see article). But he might have skipped it were it not for the looming referendum. Shocked by the near break-up of Britain in 2014 when the Scots came closer than expected to voting for independence—a triumphant Scottish Nationalist Party would have closed the nuclear-submarine base at Faslane, with worrying implications for NATO—Mr Obama has decided to speak his mind.

NATO and the EU (and its previous incarnations) have been the basis of America’s post-war engagement in Europe. The EU may be unexciting, with confusing institutions and rules, but seen from Washington, it has been a huge success.

In the first place it has helped to stop Europeans killing each other and thus reduced the need to send American armies across the Atlantic to fight. More recently, it provided both an example and magnet for the countries of the former Soviet empire. The EU’s important part in ending the cold war on Western terms, and its setting of democratic norms and values for aspirant members from the east, has been of incalculable benefit to America.

It is to Europe that America turns when something needs doing in the world that it either cannot or does not want to undertake alone. Its first port of call is still likely to be NATO. But it was the EU’s embargo on Iranian oil exports rather than American sanctions that brought Iran to the negotiating table and paved the way for the recent nuclear deal. It is EU sanctions on Russia that have substantially raised the costs of Moscow’s aggression in Ukraine. It is to the EU that America looks as a main partner in the fight against jihadist terrorism.

If the EU is a critical part of the West’s security architecture, it is even more fundamental for world trade. Should the negotiations between America and the EU to establish the Transatlantic Trade and Investment Partnership (TTIP) succeed, it will be the biggest bilateral trade deal in history. The TTIP has its opponents on both sides of the Atlantic, but the gains are worth having. A study by the Centre for Economic Policy Research estimated possible benefits at up to €119bn ($134bn) a year for the EU and €95bn for America. A British government report suggested a gain for Britain of £100 billion ($144 billion) over ten years.

From the outside in
 
Without Britain’s free-trading tradition and voice in the EU it is unlikely that the TTIP would have got this far. Were Britain to leave, it could deal a mortal blow to the treaty. If it still went ahead, Britain would find itself looking forlornly in from the outside. “I imagine the White House is absolutely bewildered by the proposal to leave,” says Dana Allin of the International Institute for Strategic Studies, a think-tank.

All Britain’s allies and friends outside Europe are at least as flummoxed. The other Anglosphere countries (Canada, Australia and New Zealand) are horrified. It matters less to them, but the Indians and the Japanese, who are big investors in Britain, are quietly dismayed.

India’s prime minister, Narendra Modi, says he sees Britain as “our entry point into the EU”.

Even China hopes Britain will stay in. Only Russia’s Vladimir Putin is cheering the Brexiteers.

Mr Obama’s concerns go beyond a Britain intent on self-harming. He fears the smouldering forces of nativism, populism and isolationism could be ignited across Europe by Brexit. The long euro-zone crisis has left raw scars, while the massive inflow of migrants from the war-torn Middle East is creating new divisions and anxieties.


In Washington’s view, the last thing Europe needs is for Britain to give its foundations a further hefty kick. As David Miliband, a former British foreign secretary, put it: “Brexit would be an act of arson on the international order.” Brexit on its own might not be a catastrophe for America, says Mr Allin, “but it could be a stage in the unravelling of the Western liberal order.” No wonder Mr Obama is worried.

Leaders of the Leave campaign—including the mayor of London, Boris Johnson—have got their retaliation in first, calling Mr Obama’s anticipated pro-EU message “hypocritical” because America would never consent to pool its sovereignty as Britain must do in the EU. Mr Johnson, who hopes to become prime minister should Brexit win and David Cameron fall, appears not to have heard of NATO, which obliges America to go to war should any other member be attacked. On April 20th, when eight former American treasury secretaries described Britain’s departure from the EU as a “risky bet” that would jeopardise the City’s role as a global financial centre, their advice was derided as an attempt to belittle Britain’s place in the world.

How much a warning from Mr Obama will pierce voters’ consciousness is hard to gauge. He is more popular in Britain than he is at home, especially with the young. If Mr Obama talks frankly about the perilous future of Britain’s trading relationships, and the weakness of its negotiating hand should it stand alone, he may hit home.

As for the special relationship, Britain will continue to be an important security partner for America because it has the biggest defence budget in Europe and the most deployable armed forces. The unique intelligence relationship will also endure, although it will have less value to America if Britain is excluded from EU information-sharing arrangements.

But so much of the case for Brexit is built on the idea that a buccaneering Britain would forge wonderful new partnerships with powerful and dynamic countries outside Europe. When Britain’s oldest and closest partner says, sorry, you won’t be nearly so interesting to us in the future if you take this step, that idea crumbles.