In 2003, the opening line of the so-called European Security Strategy was as follows: Europe has never been so prosperous, so secure nor so free.

By contrast, the first lines of the 2016 Strategy are the following: we live in times of existential crises, within and beyond the European Union. Our Union is under threat.

And it's true. European security has taken a turn for the worst. The world has become more complex and less predictable. As we speak, the Western solidarity is being tested. And in a world that is tilting towards fragmentation and polarisation, a debate about the very foundations of trusted institutions is ongoing. Europe and the United States are not exempt from this fragmentation and polarisation. On the contrary: we seem to be stricken by them.

In these times of great uncertainty, I firmly believe that unity is required above all. A far greater unity of intent and a much greater unity of effort than we witness today. If not, we might run the risk of serious damage to the zone of peace and stability that we have built over so many decades, with perseverance and sagacity.

The surge of globalization in the past 25 years has led to an enormous increase in wealth, well-being and freedom. It has benefited large numbers of people. And yet, many people in Europe and the United States are clearly also chafing under the pressures of globalization. Without a doubt, there is a strong and understandable desire among many citizens to ‘take back control’. By closing borders, by raising levies and protectionist walls, by reaffirming national identities. And even by leaving international institutions such as the EU.

So, one of the central challenges we face today, I believe, is therefore this: how can we restore control – as well as a sense of control among our citizens – without resorting to measures which will result in less jobs, less well-being and less freedom?

It is obvious that we have to decisively defeat the terrorists who attack us. That we have to combat international organised crime. That we have to stem the tide of refugees.

And to achieve all of this we need to continue our close cooperation. Within Europe, within the United States and within the Transatlantic Alliance. We need to bolster a sense of belonging for all our citizens. We need to maintain the international outlook that has also brought us so much that is good. And we need to uphold the values that are the very core of our being as well as the key to our success. Just building walls and fences will simply not work.

Of course there are many dimensions to this question of restoring a sense of control. But of one thing I am convinced: that in an uncertain world the armed forces will play a crucial role in helping us to restore this control. By bolstering our security and by bringing stability to the world around us, and perhaps even by strengthening a sense of belonging among our citizens.

But let me be clear: the challenge is as much political as it is military. In an increasingly insecure Europe, we need to maintain unity above all. Geopolitical developments and wider changes in the security context underscore the need for truly acting in unison.

Over the past years, in my capacity as the Dutch Defence minister, I have consistently voiced the need to strengthen European defence. I consider it high time to position Europe as a reliable, credible, capable and convincing security provider, in its immediate region and beyond. This is of crucial importance, particularly in order to maintain a strong and politically viable transatlantic relationship. We simply cannot expect our American friends to continue to bear the brunt of the security burden when European interests are so clearly at stake.

Important progress has been made. But we have also suffered a severe setback: the prospect of the UK's departure from the EU.

Now, the outcome of the UK referendum does not mean that the threats and challenges we face have disappeared. Neither does it mean that each nation will be better off acting on its own rather than as part of a collective. On the contrary. There are several wars out there, wars that require us to respond. So we have to forge ahead. Failure to do so risks jeopardising our security and that would be reckless.

And yes, of course, the Brexit-dust will have to settle. And true, we should not forget that the UK remains a European country with important military capabilities, as well as an important ally in NATO, committed to the defence of Europe.

So, when discussing the future of European defence, I believe it to be important to look for pragmatic solutions that will facilitate our cooperation.

Though, it is clear that no country on the face of the earth can face today’s challenges alone. They are simply too complex. They also tend to be borderless. Think of the crises in Syria, Iraq, Libya. The cruelty of Da’esh, Al-Qaida and other terrorist groups. The nuclear swashbuckling. All of these crisis can have huge repercussions at home.

Our American allies expect us, the Europeans, to step up to the plate. And rightly so. At the same time, I hasten to add that the world continues to need an outward looking and vibrant United States, a United States in a strong transatlantic partnership with Europe. Not a United States where congress is vowing to block whatever the President tries. Or a United States with a president acting in splendid national isolation.

Years of international gridlock is something we simply cannot afford. We need each other to be our best. We share global interests. And one thing is certain: if we do not take the initiative, others will take the helm and decide international events.