In Berlin's German Historical Museum, a grainy black-and-white film clip plays over and over again. Visitors stop first out of curiosity and then keep watching, unable to pull themselves away.
A young American president, 40 years ago, stands on a podium in a town square. More than 300,000 people are cheering with all their might (some historians put the crowd at 1 million). He is saying, "All free men, wherever they may live, are citizens of Berlin, and therefore, as a free man, I take pride in the words, 'Ich bin ein Berliner' (I am a Berliner)."
The president is John F. Kennedy of course, and the moment captured in that film is one of the iconic events of the Cold War. To see it now, in this place, is to understand the troubled nature of American power today.
Germany staged the special exhibit on JFK, which runs until October, as a tribute. But it was impossible to miss the irony. Germans have been among the fiercest European critics of the U.S. policy in Iraq, and only a few weeks before it opened, German protesters carried signs pointedly informing President George W. Bush, "You are not a Berliner."
"The transatlantic partnership is more important than ever," German Foreign Minister Joschka Fischer claimed at the exhibit's opening.
But what Germans were saying, privately and publicly, as they relived that long-ago moment, underlined how uncertain that partnership has become.
"The United States at (Kennedy's) time combined military, economic, cultural and moral leadership," Alexander Longolius, a member of the 1963 Berlin City Council, recalled wistfully to Deutsche Welle broadcasting service. "Kennedy stood for all that."
Images aren't history. When Kennedy delivered his speech on June 26, 1963, the wall built by the East German government to divide the old German capital was just two years old. Despite Kennedy's stirring words of defiance, the West had acquiesced in its construction.
The alternative, as everyone knew at the time, was war. The East Germans and their Soviet backers had threatened to end Western allies' postwar occupation rights in Berlin, claiming the "free sectors" of the city were subverting and weakening the socialist regime.
Then-West Berlin Mayor Willi Brandt appealed to the allies to put more troops in their sector in response. The Soviets warned they would mobilize.
Kennedy sent his vice-president, Lyndon Baines Johnson, to Berlin to calm things down, and Johnson reported back that he hoped they could neutralize Brandt's "stupid" idea. In a letter to Brandt, Kennedy said no one ought to assume "that we should go to war on this point."
Instead, to the relief of the White House, construction of the wall relieved the pressure. Allied rights in West Berlin were left unchallenged, while the East Germans could finally stop the westward flow of money and people that was undermining their regime.
Brandt and other Berliners were furious. Signs went up around Berlin attacking the American "betrayal." So Kennedy went to Berlin himself.
Photos of the U.S. president looking grimly past the wall at the Brandenburg Gate were as powerful as the speech he gave later at Berlin's Rudolph Wilde Platz. What Kennedy had achieved was to cloak an unsatisfactory compromise in a symbol of defiance and solidarity that was to last for another 26 years until the wall finally came down.
It was a lesson that Europeans have not forgotten.
Europe's current unease with American power makes a poignant contrast with the belligerence of Berliners during the 1960s crisis. Today, most Europeans would agree that the deployment of military force is self-defeating unless it is enveloped in an appropriate political context -- with clear aims, a coherent strategy and widespread support.
Was Washington's decision not to block the wall a policy failure that cemented the divisions of Europe for decades? Possibly, but the alternative could have been worse.
The United States chose instead to use its weapons of moral leadership. "The U.S. and the world knows we will never start a war," Kennedy said in another remarkable speech a few weeks before his Berlin visit.
Needless to say, it hasn't always lived up to that pledge. But today in Iraq, the contrast between its goals and its actions has badly undermined U.S. authority.
JFK finally crossed the wall. His taped words now echo in the former East Berlin, where the historical museum is located -- a 15-minute walk from Brandenburg Gate.
We are still Berliners. But we are not yet Iraqis.
Stephen Handelman, a frequent commentator on crime and terrorism for publications including the New York Times and the Toronto Star, is the author of Comrade Criminal: Russia's New Mafiya.