Like many on both sides of the Atlantic, I watched President Barack Obama’s recent visit to Europe with great interest. And not just because this visit has taught us that President “O’Bama” is actually Irish — or the fact that he can trace his roots to the British Army (he is the grandson of a Kenyan who served as a cook in the Royal Army) but because the trip highlighted the importance of the transatlantic relationship to millions — including myself.

Like many Americans, I can trace my roots to Europe — to 1950 when the Vlasic family traveled from war-torn Europe to Ellis Island, New York. They were originally from Slovenia, but the Nazis moved them to Germany. And some 60 years later, it hardly crosses my mind to think that the world is a very different place than when an immigration officer stamped a passport bearing the name “Vlasic” in 1950. Countries that were once recovering from war are now at peace — and not only are they no longer fighting, but they are working together to bring peace and prosperity to the world.

It was a Fulbright Scholarship that brought me to Europe after Georgetown University law school, and led to my service on the U.S. delegation to the Pan Am 103/Lockerbie trial, and later to the U.N. war crimes tribunal for the former Yugoslavia.

It was while serving at the tribunal that I witnessed, firsthand, the critical importance of the trans-Atlantic relationship and how it has led to numerous successes and the advancement of international justice and the rule of law. Indeed, in the first case I worked on at the tribunal, the Srebrenica genocide case, the lead investigator was from France and the lead prosecutor was from the U.S. Department of Justice. Later, in the Slobodan Milosevic case, the lead prosecutor was a British QC, while my supervising prosecutor was from New York. It was a privilege to learn from officials from both sides of the Atlantic as we served together to bring some sense of justice to those slaughtered in Bosnia. Our success in the Balkans is a direct result of strong trans-Atlantic relations.

In my more recent postings, serving as a White House fellow to Secretary of Defense Robert Gates and working on President Robert Zoellick’s Stolen Asset Recovery (StAR) Initiative at the World Bank, I’ve noticed that like-minded Americans and Europeans, with their shared values and beliefs, are working together to confront some of the greatest challenges of our time.

I’ve seen it firsthand in Iraq and Afghanistan — Americans and Europeans striving to bring some semblance of peace and prosperity in war-torn regions. And our partnership is not just a military one — reinforced by the North Atlantic Treaty Organization (NATO), the strongest military alliance this world has ever known — but also a civilian and economic one.

It was in Mosul, Iraq, that I met a young Italian woman who briefed Secretary Gates regarding her provincial reconstruction team, and how she was working to improve the agricultural output in Iraq. And it was in Kandahar, Afghanistan, where I saw Dutch officials, working with Americans, trying to devise effective ways of working with tribal leaders and local government. These were not conscripts forced to travel to far-away lands; these were European and American volunteers, working together to help better lives, based upon what is now a trans-Atlantic tradition of working together to help those less fortunate than ourselves.

Indeed, it is this spirit — and a goal of a world free of poverty — that motivates those at the World Bank every day. And thus it was not surprising that the team helping the Haitian government recover millions of dollars of Jean-Claude “Baby Doc” Duvalier’s frozen assets in Switzerland was largely transatlantic, including officials from Switzerland, France and the United States.

Put simply, ever since my time in The Hague, I’ve seen firsthand the good that comes about through the transatlantic relationship. And in many ways, that good was demonstrated just recently, with the arrest of General Ratko Mladić, mastermind of the Srebrenica genocide.

For nearly 16 years, officials from the United States and Europe have been working together to bring Mladić to justice. And [June 3], in a courtroom in The Hague, a man who was thought to be untouchable will be held to account for the slaughter of 8,000 Bosnian Muslim men and boys.

Without the transatlantic efforts of European and American officials, I doubt that Mladić would ever see justice. But due to our common values, our common interests, and a spirit that binds us, we have worked together to help extend the rule of law and help end impunity.

We must recognize that challenges of the future — whether they be economic, climate, poverty, disease, unrest — are not simple. And for any one country, they may very well be insurmountable. But thankfully, we are not forced to tackle them individually. Thankfully, we may work with our friends and allies, and within the transatlantic framework (NATO, the Atlantic Council, etc.), to tackle some of the greatest challenges to come.

Mark V. Vlasic, an adjunct professor of law at Georgetown University and a partner at Ward & Ward PLLC, served on the Slobodan Milosevic and Srebrenica genocide prosecution trial teams at the U.N. war crimes tribunal and worked with the president’s special envoy to Sudan while serving as a White House fellow to Secretary of Defense Robert Gates. He participated in the Atlantic Council’s “Young Atlanticist” summit at the 2010 NATO Summit in Lisbon. An earlier version of this essay was posted at the US Policy blog of the US Embassy in Belgium. Photo credit: Reuters Pictures.