Washington - President Barack Obama stood before America on Thursday a changed man, no longer a vehement prophet of hope, but a symbol of the perils of change in a nation riven by polarised politics.
It is only eight years since Obama erupted into public life with an electrifying call for unity at the 2004 Democratic convention.
But with Americans exhausted by wars abroad and economic malaise at home it seems longer, and the strain of crisis leadership is flecked in the president's gray hair and the dimmed fury of his rhetoric.
In his pitch for a second term at this year's convention, Obama appeared to admit that his definition of change had narrowed. He introduced toughness in place of poetry, in a speech that did not soar or inspire like his rhetoric of old.
There were few of the cascading promises that marked Obama's convention appearance in 2008 and his address seemed less the work of a man who changed politics than of someone who himself was changed by politics.
"The first time I addressed this convention in 2004, I was a younger man; a Senate candidate from Illinois who spoke about hope - not blind optimism or wishful thinking, but hope in the face of difficulty," Obama said.
"Eight years later, that hope has been tested - by the cost of war, by one of the worst economic crises in history; and by political gridlock that's left us wondering whether it's still possible to tackle the challenges of our time."
Later, Obama was looking into his soul again.
"I recognise that times have changed since I first spoke to this convention. The times have changed - and so have I," he said, vocalising the burden placed on the man who occupies the Oval Office.
"I'm no longer just a candidate. I'm the President. I know what it means to send young Americans into battle, for I have held in my arms the mothers and fathers of those who didn't return.
"I've shared the pain of families who've lost their homes, and the frustration of workers who've lost their jobs."
Unusually, Obama admitted, perhaps prompted by the reality of approval ratings below 50% and his toss up bid for re-election, that he had got some things wrong.
Swipe at Romney
"While I'm proud of what we've achieved together, I'm far more mindful of my own failings," and remembered his hero Abraham Lincoln as saying: "I have been driven to my knees many times by the overwhelming conviction that I had no place else to go."
Obama also took a stinging swipe at his Republican foe Mitt Romney and his running mate Paul Ryan, in a way that the young orator from 2004, with his call for unity might have questioned.
"My opponent and his running mate are new to foreign policy, but from all that we've seen and heard, they want to take us back to an era of blustering and blundering that cost America so dearly."
Where once Obama inspired America, it seems that now, after nearly four years in power it is the president that needs new sources of hope.
"As I stand here tonight, I have never been more hopeful about America. Not because I think I have all the answers. Not because I'm naive about the magnitude of our challenges - I'm hopeful because of you," he told supporters.
If Obama beats Republican Mitt Romney in November and secures four more years in the White House, it will have little to do with his speech on Thursday.
Unusually, Obama did not deliver the best speech of his convention. In fact it was overshadowed both by the emotional testimony of his wife on Tuesday and ex-president Bill Clinton's masterly political tutorial the next day.
The consensus of many pundits and experts after the speech was underwhelming and probably did not change the trajectory of what is shaping up as a close election.
"I think it was a very good speech, but I don't think it was his best speech," said Costas Panagopoulos, an expert in campaigns and elections at Fordham University.
But Panagopoulos said that it was unlikely a wavering swing voter would have watched Obama's meditations on fighting for change and suddenly made up his mind.
"I don't think there was enough to drive anyone off the fence," Panagopoulos said, adding that the presidential debates between Obama and Romney next month would be crucial in deciding the result of the 6 November election.
Professor Leila Brammer, a specialist in political rhetoric at Gustavus Adolphus College, Minnesota, said Obama's speech was different, because his role has now changed.
"In 2004, Barack Obama spoke as a candidate. On Thursday night, he spoke as a statesman," Brammer said.