The former Vietnam POW begins his memoir with a quotation from Victor Frankl, a survivor of Auschwitz: "Everything can be taken from man but one thing: the last of human freedoms--to choose one's own attitude in any set of circumstances, to choose one's own way."

The Marine veteran of the World War II battles of Bougainville, Guam and Iwo Jima also begins his memoir with wisdom from Frankl: "Ultimately, man should not ask what the meaning of his life is, but rather must recognize that it is he who is asked. In a word, each man is questioned by life."

You've probably guessed that the Vietnam veteran in question is John McCain, the presidential candidate whose "Faith of My Fathers" is a candid accounting of his struggle for honor. The Marine veteran is Bert Yaffe. His "Fragments of War: A Marine's Personal Journey," published this year by the Naval Institute Press, is the work of a philosophically minded tank commander who experienced some of the most murderous battles of the Pacific war.

Yaffe is very dear to me, for reasons I'll get to. But experiencing these books together helps explain a preoccupation over so many election seasons: why a presidential candidate's military service--or lack of it--is so important to so many citizens, including many who never wore their country's uniform.

McCain and Yaffe are on to something important when they both quote Frankl. If each of us is questioned by life, as Frankl says, then those who survive the horrors of battle and, in McCain's case, cruel imprisonment, are questioned more fully and profoundly.

It's true that a candidate's military service (or lack of it) cannot be taken as a guide to the kind of political leader he or she will be. But how someone offers service and endures suffering answers questions that should be asked of leaders. Most voters, I think, agree with Martin Luther King Jr.'s assertion that unearned suffering is redemptive.

In McCain's book, the lines that will rightly be cited over and over are these: "For I have learned the truth: there are greater pursuits than self-seeking. Glory is not a conceit. It is not a decoration for valor. It is not a prize for being the most clever, the strongest, or the boldest. Glory belongs to the act of being constant to something greater than yourself, to a cause, to your principles, to the people on whom you rely, and who rely on you in return. No misfortune, no injury, no humiliation can destroy it."

My reasons for pairing McCain and Yaffe here are also personal. Yaffe was a businessman in my hometown who briefly entered the electoral arena in 1970 because he opposed the very war in which McCain earned his glory. Yaffe, now 79, became in effect a second father to me after my own father died. He was also a lifelong example of how passion and reason can be allies.

Yaffe believed, passionately, that the Vietnam War was a terrible mistake for our country. He did so as a patriot who still carries shrapnel, the fragments of war, in his body, and whose own experience taught him to revere the service of John McCain and his comrades.

At a moment in our history when passion was so often transformed into hatred, Yaffe clung to the power of reason and the imperative--so important to one of his favorite philosophers, Martin Buber--of respecting the other person.

His book on his war experiences reflects this. We have come to refer to World War II as "the good war." Yaffe makes a finer distinction familiar to warriors, who know better the horrors of battle than those glorifiers of war who never experienced it. "There is, of course, no such thing as a good war," he writes, "but no amount of revisionist history has eroded my conviction that from November of 1941 to December of 1945, I was fighting the right war." And he was.

He speaks with love of his comrades and, like McCain, describes the intensity of mutual obligation born on the battlefield. But of individual Japanese soldiers and commanders, Yaffe speaks with the respect of a fellow professional.

"The young men involved in the events that I have described," Yaffe writes at the end of his book, referring to his fellow Marines, "never considered themselves brave or extraordinary. They were just clear in their minds about who they were and what they were supposed to do as their nation responded to aggressive, fanatical fascism." Yaffe, it turns out, understands glory almost exactly as McCain does, as "clarity of purpose" that "generated heartfelt camaraderie that soared into heroism."

McCain and Yaffe belong to different political parties and speak from different political traditions. But their answers to Victor Frankl's challenges were remarkably and heroically similar.