In 1926, when Congress first recognized Armistice Day -- what we now call Veterans Day -- in commemoration of the agreement that ended World War I, it declared that Nov. 11, 1918, "marked the cessation of the most destructive, sanguinary and far-reaching war in human annals and the resumption by the people of the United States of peaceful relations with other nations, which we hope may never again be severed. . . . "

Three-quarters of a century after Congress expressed that hope, how tragically naive it seems to have believed there could ever be a war to end all wars. Yet when the Cold War concluded, we allowed ourselves to believe it had been the war to end all wars. We knew in 1991 that prior victories in prior wars had led us to delusions of eternal peace, but now that we had won the "long, twilight struggle" to which John Kennedy had called us, what was left to win? History had come to an end; mankind had chosen, once and for all, its optimal organizing principles. Civilization had dawned anew.

That brave new millennium lasted all of a decade, of course. Four hijacked jetliners forced us to adjust our eyes to the twilight once more.

As there will always be wars, so will we always call upon the young and brave to fight them. I've spent the past two years talking to and writing about American war veterans -- mostly men who served in World War II and their sons who served in Vietnam. These are fighters of two wars, one celebrated, the other reviled; one victorious, the other futile.

But the character of the war did not determine the character of the warrior. Veterans of both wars went overseas possessed of idealism as only youngsters can be, willing to sacrifice their lives for the good of their comrades and countrymen. And veterans of both wars have for decades lamented their fallen friends by day and dreamed of war's horror by night.

"My experience in war wasn't all that different from my son's," a veteran of Sicily, Italy and France told me. "It was a different experience because it was different people, but when you undergo gunfire, I don't think there's a difference." Combat deeply unites those who have taken part in it and deeply divides them from everyone else. I am not a veteran, and although I've tried my best in long hours of conversation to understand what these men went through, I never will be able truly to appreciate what combat is like, nor, I believe, can anyone else who has not been there. One veteran of the Pacific said, "It's very hard to talk about this to people who haven't experienced it. If a person has felt it, then they understand what I'm talking about. And not particularly the words that I put out -- they can feel the feeling and the energies that come out of me. But if I'm dealing with somebody else that has never experienced that kind of thing, I can't converse with you."

War changes people. Thirty-five or 55 years after the fact, men may have trouble recalling the date they stormed a beach or the name of the lieutenant who led them on a patrol. But they never forget their feeling the first time they were shot at or saw a body blown apart or heard that a buddy had been killed. They never forget the sights and sounds and smells of living with death on a daily basis.

"When Vietnam got going," a veteran of Iwo Jima recalled, "I said, 'Sonofabitch, we don't need any more recruits for the VFW.' I cried an awful lot when my boy went overseas. Mom and I cried our hearts out."

This day, 84 years after the end of the war to end all wars, the pool of qualified recruits for the Veterans of Foreign Wars is growing again -- in Afghanistan now, and soon, perhaps, in Iraq. Whether we endorse or dissent from decisions our leaders make, in our names, to put young Americans in harm's way, we shirk our duty as citizens if we avert our eyes from what they are about to encounter and, if they survive, what they will live with the rest of their lives. We have many ways to honor our veterans -- parades, monuments, simple expressions of thanks. But this Veterans Day in particular, if we wish to honor the sacrifice of yesterday's warriors, we need to think hard before we ask it of the warriors of today.

Michael Takiff is the author of "Brave Men, Gentle Heroes: American Fathers and Sons in World War II and Vietnam," a collection of oral histories to be published next year.