On an Army parade ground rich with history, President Clinton paid solemn tribute on Monday to the generation that won World War II and prevailed in the Cold War, thanking veterans for their sacrifice but warning that the nation still faced “forces of darkness” abroad and at home.

“Because of all you did, we live in a moment of hope, in a nation at peace,” Clinton told veterans in a ceremony at Fort Myer, Va., before flying off to Moscow for V-E Day commemorations there today. “For the first time since the dawn of the nuclear age, no Russian missiles are pointed at our children.”

But Clinton, the first American president born after World War II, added: “There is one thing that even you could not do, that no generation can ever do. You could not banish the forces of darkness from the future. We confront them now in different forms all around the world, and painfully, here at home. But you taught us the most important lesson: that we can prevail over the forces of darkness, that we must prevail.”

Clinton laid a wreath at the Tomb of the Unknown Soldier at Arlington National Cemetery on Monday morning, and then at the 50th anniversary commemoration, Clinton reviewed troops, bands and aircraft from all the armed forces.

“The saga of hope emerged from the ashes of a horror that defies comprehension still: the Nazi death camps and the gas chambers and crematoriums with proof of man’s infinite capacity for evil,” Clinton said, surrounded by veterans who were on active duty on May 8, 1945. “In the empty eyes of the skeletal survivors was a question that to this day has never been answered: How could this happen?”