It was there on October 6th that he suffered a humiliating defeat when his appeal to the International Olympic Committee fell on deaf ears and Chicago's bid to host the Summer Games in 2016 was decidedly rejected.
"I urge you to choose Chicago," the president said that day in Copenhagen. "I urge you to choose America."
The appeal was ignored and Chicago was the first of the final four would-be host cities to be eliminated.
Eleven weeks later he'll be in Copenhagen again in search of an international agreement to counter advances in global warming.
"It's essential that all countries do what is necessary to reach a strong operational agreement that will confront the threat of climate change while serving as a stepping-stone to a legally binding treaty," Mr. Obama said about the conference.
But no one expects a legally binding treaty - and a "strong operational agreement" may be beyond reach as well.
Nevertheless, Mr. Obama still thinks it's worth his time and effort to travel 8,100 miles to spend 10 hours in the Danish capital.
He'll get a chance to address the scores of other world leaders attending the end of the conference. It'll be another high-stakes moment for him on the world stage - one where he can make his case about confronting the threats posed by global warming.
If nothing else, the leaders will pose for a class photo they can take home as a souvenir instead of a treaty.
A senior administration official calls the Copenhagen conference the "most complex negotiation" Mr. Obama has faced since taking office. And if he comes home without a deal, he'll keep trying, says the official.
Just like his approach to health care legislation.