It is a curious fact of American history that many of the great men of the Republic never ended up in the White House.

Benjamin Franklin was too old, having turned 83 the year of the first presidential election. Henry Clay - despite five attempts to make it to 1600 Pennsylvania Avenue - had to settle for being one of the most important members in the history of the U.S. Senate. Daniel Patrick Moynihan, one of the preeminent public intellectuals of the late 20th century, was perhaps too blunt for the presidency, once telling a Third World audience "Food growing is the first thing you do when you come down out of the trees. The question is how come the United States can grow food and you can't?"

As John McCain enters into the twilight of his legislative career, it is virtually certain that he will never be enshrined in the presidential pantheon. But whether he will bequeath a legacy in the same stratum as Franklin, Clay, or Moynihan is far more debatable.

So far, McCain's biggest legislative accomplishment as a U.S. senator has been the McCain-Feingold Act, restricting the means and manner of campaign finance. This law, of course, has totally purified American politics from the taint of moneyed influence. No, really. Stop laughing.

But regardless of one's feelings about the effects of campaign finance reform, this much is certain: it is not the stuff of a truly historic career. One hundred years from now, the history of the 21st century will be able to be competently written without so much as a word on how the electoral process was funded. Nor are McCain's good government crusades against earmarks, Pentagon waste, or pork-barrel spending - however noble - defining and enduring improvements on the American landscape.

Yet perhaps now, in the shadow of his presidential defeat, Senator McCain has found his moment in history.

The occasion is President Obama's decision to release to the public documents describing the terrorist interrogation techniques of the Bush Administration. Sensible patriots can be forgiven for ambivalence towards the president's gesture. In one light, it is perhaps a renewal of the nation's charter principles. In another, it is possibly a gesture of weakness - a limp concession delivered out of fear that the sins of the fathers will be visited upon the sons.

What cannot be debated, however, is that this is a matter of the gravest importance. It involves serious and sophisticated questions about the lengths to which a free society may go to defend itself. What does it profit a nation, after all, to gain the whole world and suffer the loss of its soul?

Perhaps no issue in the brief history of the Obama Administration has been as worthy of the president's inaugural call to "a new era of responsibility." Yet on that front, President Obama has failed. And the man he vanquished at the polls has succeeded.

Had the president truly wanted to "acknowledge [mistakes] and move forward" as he said in an April 20 speech at the CIA, the course before him would have been clear. He could simply have signed the January executive order banning the techniques, informed the nation that we were turning over a new leaf, and proceeded to put his own stamp on the war on terror.

Instead, Obama has chosen to lead the country in a sort of nationwide catharsis. With the memos related to the CIA's interrogation techniques now made public, every last detail will be fodder for the two most capricious species in American life - cable news producers and congressional committee chairmen. And when the Pentagon releases photos of alleged prisoner abuse later this month, the national temperature will only rise.

A congressional investigation is already underway. Influential liberals are calling for a federal appellate judge who authored some of the memos to either resign or be impeached. Some in Congress are beginning to demand a special prosecutor tasked with ferreting out wrongdoing in the CIA's interrogation program. Even ostensibly serious commentators are publicly fantasizing about show trials that punish members of the previous administration ranging from Justice Department lawyers to Obama's predecessor in the Oval Office.

Into these fever swamps has waded John McCain, a man whose life was nearly extinguished by the agony of torture four decades ago and half a world away.Of the 537 men and women elected to federal office, he is one of only two who ever had to stiffen their spines and peer into that abyss.  And because of his national platform, no one speaks to the American people on this issues from a position of greater authority.

McCain was adamantly opposed to the methods used by the Bush Administration. But in this hour of grave national unseriousness, he has chosen to be the adult in the room.

After years of protesting the extreme techniques, McCain's message of late has been simple: dutiful public servants attempting to shield the American people from another terrorist attack shouldn't be prosecuted because they failed to anticipate that a future administration wouldn't like their advice. If we expect these men and women to devote the full force of their talents to keeping the nation safe, then we have to promise them something better than victors' justice. Only a suicidal society flogs those who are trying to save it.

At the heart of liberal democracy, there is a notion - humble and just - that policy differences are not to be criminalized. Destroy that standard and you substitute the raw force of power for the cool reason of law. If John McCain's courageous stand can preserve that principle, he will have saved a hallmark of the American system. And he will have earned his place in history.

Correction: An earlier version of this article stated that Senator McCain was the only federal elected official to undergo torture. Rep. Sam Johnson (R-TX) also experienced torture while a prisoner of war in Vietnam. The author regrets the error and honors Rep. Johnson’s service to his country.