Ahead of Britain’s EU referendum, the outgoing US president Barack Obama talks about his country’s special relationship with the UK, his challenges and the tests his successor will face when he steps down.

In 1939, president Franklin D Roosevelt offered a toast to King George VI in the White House. “I am persuaded that the greatest single contribution our two countries have been enabled to make to civilisation and to the welfare of peoples throughout the world,” he said, “is the example we have jointly set by our manner of conducting relations between our two nations.”

Nearly 80 years later, the United 
Kingdom remains a friend and ally to the
 United States like no other. Our special
 relationship was forged as we spilt blood
 together on the battlefield. It was fortified
 as we built and sustained the architecture
 for advancing stability and prosperity in
 Europe and our democratic values around 
the globe. From the ashes of war, those who
 came before us had the foresight to create 
the international institutions and initiatives 
to sustain a prosperous peace: the United 
Nations and Nato; Bretton Woods, the
 Marshall Plan and the European Union. Their efforts provided a foundation for democracy, open markets and the rule of law, while underwriting more than seven decades of relative peace and prosperity in Europe.

Today we face tests to this order – terrorism and aggression, migration and economic headwinds – challenges that can only be met if the United States and the United Kingdom can rely on one another, on our special relationship and on the partnerships that lead to progress. We must be resolute and adaptive in our efforts to prevent terrorist attacks against our people and to continue the progress we are making to roll back the threat posed by Islamic State (ISIL) until it is destroyed.

We must work to resolve political conflicts in the Middle East – from Yemen to Syria to Libya – so that there is a prospect for increased stability. We must continue to invest in Nato so that we can meet our overseas commitments from Afghanistan to the Aegean and reassure allies who are rightly concerned about Russian aggression. And we must continue to promote global growth so that our young people can achieve greater opportunity and prosperity.
The question of whether or not the UK remains a part of the EU is a matter for British voters to decide for themselves. That said, when President Roosevelt toasted our special relationship that night, he also remarked that we are friends who have no fear of each other. So I will say, with the candour of a friend, that the outcome of the decision is a matter of deep interest to the United States. The tens of thousands of Americans who rest in Europe’s cemeteries are a silent testament to just how intertwined our prosperity and security truly are. And the path they choose now will echo in the prospects of today’s generation of Americans as well.

As citizens of the United Kingdom take stock of their relationship with the EU, they should be proud that the EU has helped spread British values and practices – democracy, the rule of law, open markets – across the continent and to its periphery. The European Union doesn’t moderate British influence – it magnifies it. A strong Europe is not a threat to Britain’s global leadership; it enhances Britain’s global leadership. The United States sees how [Britain’s] powerful voice in Europe ensures that Europe takes a strong stance in the world and keeps the EU open, outward-looking and closely linked to its allies on the other side of the Atlantic. So the US and the world need its outsized influence to continue, including within Europe.

In this complicated, connected world, the challenges facing the EU – migration, economic inequality, the threats of terrorism and climate change – are the same challenges facing the United States and other nations. And in today’s world, even as we all cherish our sovereignty, the nations who wield their influence most effectively are the nations that do it through the collective action that today’s challenges demand.
When we negotiated the historic deal to verifiably prevent Iran from developing a nuclear weapon, it was collective action, working together with the permanent members of the UN Security Council and Germany, that got the job done. And the EU’s seat at the table magnified the United Kingdom’s voice.

When the climate agreement in Paris needed a push, it was the European Union, fortified by the United Kingdom, that ultimately helped make that agreement possible. When it comes to creating jobs, trade and economic growth in line with our values, the UK has benefited from its membership in the EU – inside a single market that provides enormous opportunities for the British people. And the Transatlantic Trade and Investment Partnership with the EU will advance our values and our interests and establish the high-standard, pro-worker rules for trade and commerce in the 21st century economy.

This kind of cooperation – from intelligence-sharing and counter-terrorism to forging agreements to create jobs and economic growth – will be far more effective if it extends across Europe. Now is a time for friends and allies to stick together. Together the United States, the United Kingdom and the European Union have turned centuries of war in Europe into decades of peace and worked as one to make this world a safer, better place. What a remarkable legacy that is. And what a remarkable legacy we will leave when, together, we meet the challenges of this young century as well.