On a rainy October night in 2006, I took a cab to the John F. Kennedy library here to conduct a very public interview. As we pulled up, the driver asked, "Who's on the program?"
"Barack Obama," I said.
"Oh," he replied, "our next president."
I mentioned this to then-Senator Obama during the program and he got a good laugh out of it. He hadn't yet announced that he was running. The capacity crowd in the auditorium was clear about what it wanted. It cheered every mention of a possible run. Obama-mania was already well under way, and it would only grow.
I was back at the library this week to interview Gwen Ifill about her new book, "The Breakthrough: Politics and Race in the Age of Obama," and I wondered aloud about this continuing love affair with all things Obama - the feverish excitement, the widespread joy and pride, and the remarkable surge of hope in an otherwise downbeat, if not depressing, period.
Where was all this coming from? What was it about?
Yes, as everyone agrees, Mr. Obama is handsome, fit, smart, and a great speaker. As Ms. Ifill noted in her book, "Voters are attracted to youth, vitality and change."
And Americans tend to get giddy over winners, especially underdogs who take the measure of a foe thought to be impregnable - in this case, the mighty forces carefully assembled over several years by the Clintons.
And it's not just the president himself who looks good. Even the shameless purveyors of fantasy at central casting would blush at the thought of crafting a family as picture perfect as the Obamas. So, yes, there is an awful lot to like about the Obama phenomenon.
But I've seen charismatic politicians and pretty families come and go like sunrises and sunsets over the years. There was something more that was making people go ga-ga over Obama. Something deeper.
We've been watching that something this week, and it's called leadership. Mr. Obama has been feeding the almost desperate hunger in this country for mature leadership, for someone who is not reckless and clownish, shortsighted and self-absorbed.
However you feel about his policies, and there are people grumbling on the right and on the left, Mr. Obama has signaled loudly and clearly that the era of irresponsible behavior in public office is over.
No more crazy wars. No more torture, and no more throwing people in prison without even the semblance of due process. No more napping while critical problems like the Israeli-Palestinian conflict, global warming, and economic inequality in the United States grow steadily worse.
"We remain a young nation," Mr. Obama said in his Inaugural Address, "but in the words of Scripture, the time has come to set aside childish things."
On Wednesday, his first full day in office, the president took steps to make the federal government more transparent, signaling immediately that the country would move away from the toxic levels of secrecy that marked the Bush years.
"Transparency and rule of law will be the touchstones of this presidency," he said. It was a commitment to responsible behavior, and a challenge to the public to hold the Obama administration accountable. It reminded me of the wonderful line written into a federal appeals court ruling in 2002 by Judge Damon Keith:
"Democracies die behind closed doors."
This has been the Obama way, to set a responsible example and then to call on others to follow his mature lead. In Iowa, after his victory in the Democratic caucuses a year ago, he promised to be "a president who will be honest about the choices and challenges we face, who will listen to you and learn from you, even when we disagree, who won't just tell you what you want to hear, but what you need to know."
In a cynical age, the inclination is to dismiss this stuff as so much political rhetoric. But Mr. Obama carries himself in a way that suggests he means what he says, which gives him great credibility when he urges Americans to work hard and make sacrifices, not just for themselves and their families but for the common good - and when he tells black audiences that young men need to hitch up their trousers and behave themselves, and that families need to turn off the TV so the kids can do their homework.
Or when he says of the many serious challenges facing the nation, as he did in his Inaugural Address: "They will not be met easily or in a short span of time. But know this, America: They will be met."
The bond is growing between the nation and its new young leader. Let's hope it's a mature romance that weathers the long haul.