The Gallup Organization just came out with a new poll asking Americans to identify the nation’s greatest presidents. Ordinarily you might dismiss any survey that puts John F. Kennedy and Bill Clinton among the top five chief executives and places each of them ahead of Franklin Delano Roosevelt. But I’m about to argue that this might be the most important, and most revealing, poll of 2007.

I may be among the most fervent supporters of Kennedy’s presidency, but even I am not prepared to argue that he was a greater president than FDR, or for that matter better than Theodore Roosevelt or Andrew Jackson. Many devout conservatives have surprised themselves and come to see the virtue of the presidency of Clinton, but none of them would rank the 42nd president ahead of George Washington, the first president. Most professional historians consider Lincoln, Washington and FDR the greatest presidents, the standards by which others are judged.

But as the nation begins another presidential election cycle, polls like the one undertaken by Gallup may be immensely instructive – not for what they tell us about the public’s view of the virtues they see in previous presidents, but for what they tell us about the public’s views of the virtues they implicitly seek in future presidents.

On the surface, there’s very little that Abraham Lincoln and Ronald Reagan (ranked Nos. 1 and 2, respectively) have in common with Kennedy, Clinton and FDR (who round out the top five). Lincoln kept together a country that was divided geographically as well as metaphorically in war, while Roosevelt presided over a country that was remarkably united in war. Lincoln, Clinton and Roosevelt were lawyers, but Reagan and Kennedy were not. Lincoln was a brooder and probably suffered from depression; Reagan was relentlessly optimistic.

Clinton and Kennedy thought of themselves as intellectuals, but Lincoln, Reagan and Roosevelt were intuitive, and maybe smarter as a result. Kennedy, Clinton and Roosevelt attended elite private colleges, but Lincoln didn’t have a college education at all, and Reagan didn’t break a sweat, nor maybe even crack a book, during his Eureka collegiate years.

There are, however, a few strains the top five had in common. They were confident – of their judgment, of themselves, of their instincts, of their country. Lincoln, for example, invited his most fervent political enemies into his inner circle. Roosevelt and Reagan had the self-confidence to set a mighty, established nation on entirely new and uncharted courses. The five had strong personalities – strong enough to endure the strain of civil war on the American continent or the threat of nuclear war over Cuba, as Lincoln and Kennedy did, strong enough to charm a nation, as Reagan, Clinton and FDR did.

But self-confidence and charm are not enough to lead a nation; if they were, we wouldn’t have to waste the next dozen months in Iowa, Nevada, New Hampshire and South Carolina, and we could go ahead and nominate George Clooney for president and perhaps add Tom Brady as vice president and be done with it. And we can’t clone a previous president. If we could, the poll suggests we’d choose Lincoln, and no one who has heard the Bob Newhart riff on how modern political consultants would ruin the Gettysburg Address could even entertain the notion of transporting the great rail splitter of the 19th century to the wireless world of the 21st century.

So we’re stuck with a composite, and here’s what we might look for:

We need the fearlessness and fortitude, and the genuineness and gentleness, of Lincoln, who spoke in biblical cadences while prosecuting a bloody war to restore the Union – even as he invented a new country and grafted the idea of equality, which was not in the Constitution or even in his own early worldview, onto the American mind. We need the optimism of Reagan, who was brave enough to see morning in America and then persuasive enough to breathe a new, fresh dawn onto a weary country.

We need the resolution of Kennedy, who dared to believe Americans might be idealistic again and who, in life and then in tragic death, gave America reason to be idealistic. We need the dauntlessness of Clinton, who had the bravery to embrace ideas his own supporters reviled and the valor to transform diversity from an American burden to an American advantage. We need the resolution of Roosevelt, who dared to believe America could prevail in a world beset by depression and, worse still, by despots.

Now a personal confession: I’m trained in the writerly arts to avoid the repeated use of a single word in a single passage, and so if you return to the paragraphs above you may conclude that there is a certain awkwardness to it, a whiff perhaps of the thesaurus. You’re right. The act of writing is really the act of thinking, and you can see my own sense of discovery in the words “fearlessness” and “brave” and “dauntlessness” and “resolution.”

They’re all synonyms for the single word that describes each of the presidents Americans say they admire the most from the past – and, we might conclude, the models they might use as they select a president for a frightening and uncertain future. That word is courage. Find the candidate for 2008 who has that, and you might find the man or woman whom Americans will select to be the next president. We should be so lucky.