Henry Kissinger kept his word. Scarcely a week had passed since he underwent an angioplasty, but there he was, almost exactly on time for his lunch appointment.

He engaged in a bit of schmoozing at a couple of banquets with people like Sanford Weill, the Citigroup chairman. Then the former secretary of state sat down at the table that was once the preserve of another legendary figure, the late Philip Johnson, the architect who’d designed the restaurant more than four decades ago.

“I’m sorry that I let you down a couple of times,” Mr. Kissinger said to the reporter, referring to canceled appointments last week. In view of his heart situation, those cancellations hardly warranted an apology. But his words seemed to be entirely in character for the 82-year-old statesman. The Nobel Peace Prize and scores of other high honors and encomiums notwithstanding, Mr. Kissinger – at least to those like the reporter who had followed his academic and public-service career for 35 years – has been remarkably plainspoken and intellectually accessible.

And so the reporter was emboldened to ask a delicate question: How did Mr. Kissinger cope with all the relentless personal attacks against him, jeremiads directed not only at his record as national security adviser to Presidents Nixon and Ford, and as vicar of American foreign policy, but also the subsequent – and flourishing – period as an adviser on international relations and investments to corporations, and as the author of best-selling memoirs?

“I don’t want to pretend that I don’t notice this criticism,” Mr. Kissinger said. “Of course I notice it. But the virulence of some of these attacks is such that if one answers it, then one exhausts oneself in a guerilla war with an implacable group. So I would rely on the historical record to take care of it.”

That historical record, fashioned by a lifelong Republican who was a protege of Nelson Rockefeller, has been extraordinary by any rational measure – which is perhaps why it has invited attacks from ideologues of the left, for the most part, who often equated his pragmatism with cynicism.

Consider this: Mr. Kissinger’s secret diplomacy opened the way for re-establishing political ties between America and China in the early 1970s while Mao Zedong – who famously referred to Americans as the “running dogs of capitalism” – was still alive. His interaction with North Vietnam’s Le Duc Tho – with whom he shared the 1973 Nobel Prize – led to eventual peace in Indochina.

His ideas on detente led to triangular American-Chinese-Soviet diplomacy and the drawing of the erstwhile Soviet Union into the web of international affairs, according to Professor Dennis Kavanaugh of the University of Liverpool.

And Mr. Kissinger’s celebrated “shuttle diplomacy” between Israel and various Arab countries after the 1973 Yom Kippur War contributed significantly to developing an incremental approach toward the peace process in the Middle East and three agreements – two between Israel and Egypt, and one with Syria that is still in force.

Wasn’t he tempted to respond in kind to his critics?

“I never attack any person, nor have I replied to any of these attacks,” Mr. Kissinger said. “I think perhaps once I replied to something that was carried in the New York Review of Books. Basically, I’ve always tried to raise the debate above the level of personalities.”

Wasn’t he distressed by the rancor of public debate in America today?

“I don’t want to put anything in terms of the day-to-day issues,” Mr. Kissinger said. “I think we’re watching a change in humankind. The generation that learned by reading had a certain conceptual approach – and they would fight more ideological battles. The generation that has been brought up by the Internet has a more visual approach, and therefore the temptation to go emotional grows stronger and stronger.

“I think the Vietnam War was a sort of dividing line,” Mr. Kissinger continued. “When I started in government 35 years ago, one had many opponents. But there was a bedrock of people who were quite well informed at the outset of many of the aspects of the issues. But it’s much less today. People take positions before they’ve studied the issues. Their views on issues reinforce set positions rather than the other way around.”

For Mr. Kissinger, the notion that careful study of issues must precede any pronouncements on them has always been an article of faith. It dates back to his time when, after obtaining his Ph.D. from Harvard, he taught government there.

His book “Nuclear Weapons and Foreign Policy,” published in 1957, made the case that America’s survival and victory depended not only on its military and economic strength but also on its capacity to fight aggression in all forms. That argument – and the book in which it was developed – burnished Mr. Kissinger’s reputation as a rising star among the nation’s political scientists.

During the lunch, he recalled that time of promise.

“When I was a graduate student and a young professor at Harvard, we used to have faculty seminars with scientists and political scientists and others to discuss the implications of the nuclear age,” Mr. Kissinger said. “Most of them were Democrats, but the emphasis was national, not partisan. And it was never personal. Every point of view was welcomed.”

But as the 1960s and 1970s evolved, he said, America’s intellectual community split into two groups: “Job applicants – people who wanted government jobs- and revolutionaries, who denied that anything valid could be done unless the system was changed or destroyed.

“It was really about access to power,” Mr. Kissinger said. “It was no longer about access to ideas. The nature of the intellectual community has changed. If more and more see themselves as advocates rather than as generators and debaters of ideas, then it’s a different society.”

“What the government needs from the intellectual world is a five-year perspective, but the job applicants, like government officials, focus only a two-year perspective,” he said. “And what the revolutionaries do is to attack the premise that motivates the system. So there’s a gap now in our country.”

And how should this gap be addressed, the reporter asked?

The question elicited a reflection from Mr. Kissinger about the very meaning of America, where he came in 1938 as a refugee from Nazi Germany; where he attended high school in Manhattan’s Washington Heights at night while working during the day at a shaving brush factory; and where he was drafted in 1943 into the 84th Infantry Division and from there onto the 970th Counter Intelligence Corps.

“One lesson I drew during my time in the military was that it was important to make a difference in life,” Mr. Kissinger said. “Before that, I just wanted to be an accountant and make money. I knew after the military that I would be in public service someday – although I had no idea at the time what that public service would be.”

“One respect in which somebody with my background is different from the mainstream is that those of us who are refugees, and who have lived abroad, find it hard to accept challenges to the American Dream itself,” Mr. Kissinger said. “We’ve lived in societies with a long history. We know that history moves more slowly than American ideology, but we also know that there are very few societies with the freedoms and liberties and tolerance that America offers. We know what America meant to us when we were young. And so all these accusations of imperialist America – we don’t like that attitude. It’s almost painful to us. We like to believe there are solutions to our social and political problems.”

And what about critics of America? How does he relate to their positions?

“Student critics of America don’t bother me – that’s the face of youth,” Mr. Kissinger said. But it’s those who seek “an upheaval in America’s institutions and commitments” that disturb him.

“In any case, I don’t debate with them,” Mr. Kissinger said.

“I think that America, with all its faults and shortcomings, is still the hope of the world,” he said. “First of all, in day-to-day living, no country can offer a better life for its people. No other society is so charitable, and its people so generous in human contacts. And no other society facilitates human contact like we do in the family that is America.”

So does it puzzle him that Americans frequently seem flummoxed by what’s happening in the world out there, the very international arena that Mr. Kissinger has studied closely for seven decades?

“Most Americans don’t know much about other lifestyles around the world,” he said. “Most Americans think that most foreigners are aspirant Americans, that they would all like to come and live here. Most Americans want to be left alone by the rest of the world.”

Given such a scenario, then, the reporter asked, does it surprise him that there’s so much dislike for America around the world?

“It’s painful to observe,” Mr. Kissinger said. “But it’s also true that so many of these societies, when they get into a real crisis, turn to us. What has undoubtedly occurred in many countries, especially European countries, is that there’s been a coalescence of protest movements of the 1960s with the arrival of governments who are themselves sympathetic to these movements.”

His assertion created an opening for another question. Wasn’t the current American effort to promote public diplomacy intended to placate countries that begrudged America’s social and political objectives?

“I’m not the best person to ask that,” Mr. Kissinger said. “In my period, I had no formal public diplomacy.”

Rather, he said, his approach was to give the media “a running commentary on my thinking” so that the objectives and purposes of American foreign policy could be better disseminated to the wider public and the media could understand individual decisions when the need for them arose.

“If you have to sell every policy in retail, then you’re on an impossible ground,” Mr. Kissinger said. “That’s because the public may not always understand the context of those policies.”

Tomorrow, part two: How Mr. Kissinger sees America’s challenges in the emerging world order.