From the beginning, John F. Kerry has formed his presidential campaign around his service in the Vietnam War. But it is another war, World War II, that shaped his belief that the United States is more effective on the global stage when it works closely with other countries.
As a young boy, he saw the ruins of his mother's house in France. As an adolescent, he lived in West Berlin, where his father was a diplomat. Even as a young man, he measured his service in Vietnam against what his experience and education had taught him about the importance of international alliances.
Now Kerry's belief in the need for global partners has become one of the defining elements of his challenge to President Bush. In tonight's debate, the Democratic nominee is expected to stick to the theme he has sounded for months: Only a change in U.S. leadership will attract other countries to share the burden in Iraq.
That line of attack has not been without hazard. Bush and Vice President Cheney have used it as a basis for counterattacks, with the president portraying Kerry as wanting to submit U.S. policy to a "global test."
The practicality of Kerry's approach is itself a matter of debate. If he wins, Democratic and Republican analysts said, Kerry might enjoy a honeymoon and get more support from allies on "soft issues," such as debt relief and training Iraq's army and police. But they said additional foreign troops will be hard to come by as long as the insurgency rages.
"There is no magic bullet here. If Kerry comes into office, the mere fact that he did not start this war is not going to create a miraculous new beginning with our allies. It's only modestly helpful," said Larry Diamond, who worked with the U.S. occupation government in Iraq. "What leaders are going to want to face their publics as the violence continues and say, 'We need to put troops on the ground' "?
Still, Kerry's devotion to alliances forms the core of his worldview, longtime friends and associates say, an outlook shaped as much by biography as by ideology. His handlers and his detractors have focused on his service in Vietnam, but a more essential chapter in his life is his youth in postwar Europe.
In 1947, not long after the war ended, Kerry's mother took him to her childhood home in the Brittany region of France. Rosemary Kerry, who had moved to the United States as a young woman, told her son that she had fled on a bicycle, ducking machine-gun fire from German bombers.
Kerry, then 4, held his mother's hand as their feet crunched over stones and shards of glass. The walls were heaped at their feet. A chimney rose above the rubble; a blackened stairway broke off at the sky.
The Nazis had used her house as a military post. Before they retreated, they blew it up, Kerry said in an interview, because his grandparents had been friendly with the British prime minister, Winston Churchill.
"It's my earliest memory," Kerry said, sitting in his study in his Boston home. "She was sobbing; I was perplexed." He reached for a photograph of the Brittany house and traced the black-and-white lines: "Here's the chimney. The grass was tall."
Kerry keeps a second old photograph in his home. It is of his father, in a white U.S. Army Air Corps uniform, smiling beside a warplane. Richard Kerry volunteered before the Japanese struck Pearl Harbor.
These two images of war -- of mother and of father -- were etched in the boy's consciousness. The Allied forces had liberated his mother's home, and the Allies' cause had inspired his father's conscription. Evil, Kerry has said he learned, was defeated by an international alliance.
He cites a second, visceral experience as cementing his faith in international ties. Kerry was 11 when his family moved from Washington to Berlin -- old enough to understand that the bombed-out buildings were from World War II, young enough to pretend that they were still smoldering.