CHARLOTTE, N.C. — He warned them in 2008, and when he formally opened his re-election campaign in May, he put it in his speech again. He will “never be a perfect president,” he said, a line he now repeats at stop after stop. The unspoken subtext: It’s not my fault if you didn’t listen or expected too much.


If rapturous supporters in Denver four years ago were not paying attention, those expected here on Thursday night surely know better. This is not a perfect president; this is a proud yet humbled president, a confident yet scarred president, a dreamer mugged by reality, a pragmatist confounded by ideology, a radical to some, a sellout to others.


This is a president who has yet to realize the lofty expectations that propelled him from obscurity to the Oval Office, whose idealism or naïveté or hubris has been tempered by four years in the fires. Long after the messiah jokes vanished, the oh-so-mortal Barack Hussein Obama is left to make the case that while progress is slow, he is taking America to a better place — and that he will be a better president over the next four years.


If Denver was all about promise, Charlotte is all about patience. Whether Americans grant the 44th president a four-year extension will depend in part on his ability to reconcile the heady aspirations of 2008 with the messy results of the four years that followed. Remade by his time in office, the candidate of change will now argue for staying the course.


Although “he certainly seems more grizzled or hardened,” as his former economics adviser Austan Goolsbee observed, Mr. Obama expresses confidence that he has figured out how to wield power in an age of political polarization and economic stagnation.


Now on his third chief of staff, he describes his change in management in sports terms, no longer picking the best overall athlete but whoever best fits the particular job. Burned by failed Roosevelt Room summits with Republican leaders and faced with implacable resistance, he has abandoned the inside game to barnstorm the country pressuring lawmakers. Once a virtual prime minister tethered to Congress, he now advances immigration, environmental and education initiatives through executive authority.


In the privacy of the West Wing, of course, there are moments when he feels discouraged by what he has not accomplished or unappreciated for what he has. “That’s been our sweet spot — finding policies that don’t make anybody happy, that make both sides angry,” he has joked, Mr. Goolsbee said. “And the experts then say, well, they didn’t do enough anyway.”


But those close to him say he takes the long view, understands things will not change as quickly as he likes, and retains his famed never-too-high, never-too-low reserve. During the dark days of summer 2011 when a grand bargain with Republicans on spending slipped away, he took a walk with David Axelrod, his strategist, to the White House basketball court and shot hoops.


“Do you ever rethink this, about whether it was worth doing?” Mr. Axelrod remembered asking.


Mr. Obama looked at him incredulously. “Of course not,” he said. “If you’re in public life, where else would you rather be?”


The Limits of Rationality


A few months ago, Mr. Obama read “Thinking, Fast and Slow,” by Daniel Kahneman, about how people make decisions — quick, instinctive thinking versus slower, contemplative deliberation. For Mr. Obama, a deliberator in an instinctive business, this may be as instructive as any political science text.


Mr. Obama, the 51-year-old Harvard law graduate, sees himself as a rational thinker and came to office with what might be called the Reasonable Person Theory of Government. If he could simply sit down and talk with other political actors, whether they be Republicans from the House or mullahs from Tehran, he seemed certain he could work something out. His faith in his own powers of persuasion was deep.


But politics is often not rational, at least not as Mr. Obama defined it. The Iranians have proved immune to Mr. Obama’s charm, as have the North Koreans, the Taliban and Vladimir V. Putin. So have the Republicans and, for that matter, even some Democrats.


After a year of failed Middle East peacemaking, he conceded being too confident that he could cajole Israelis and Palestinians into resolving age-old disputes. “We overestimated our ability to persuade them to do so when their politics ran contrary to that,” he concluded at the time.


So, too, has his reliance on oratory diminished. At first, there was no problem, it seemed, that could not be solved by a presidential address. “Race problem? Speech,” one former aide recalled. “Afghanistan? Speech.” But speeches by themselves rarely generated the action he sought.


Indeed, Mr. Obama in private sometimes expresses surprise at the constraints of the office. Lulled by his success in passing an $800 billion stimulus package 24 days after his inauguration, and perhaps not fully cognizant of the tone set by doing so almost exclusively with Democratic votes, he found that everything else came harder, like his health care program, or not at all, like climate and immigration legislation.