Sport and politics converge in a potent mix on Friday with the credibility of the US President on the line as International Olympic Committee (IOC) members choose the venue for the 2016 Summer Olympics.
The stakes could hardly be higher when more than 100 IOC members gather at Copenhagen's Bella Convention Centre to choose between the rival bids of Chicago, Madrid, Rio de Janeiro and Tokyo.
Though the contest has long been regarded by most Olympic experts as the closest ever, with four potential winners in the field, there is no doubt that the Obama factor weighs heavily and has ensured Chicago takes the role of front-runner.
No incumbent US President has ever addressed an IOC session before but Barack Obama has taken the boldest of risks to his political reputation by deciding to appear in person to back his home city campaign.
While he flies in overnight from Washington and goes straight into the IOC session, First Lady Michelle Obama will have been in the Danish capital for 48 hours, conducting a breathless series of one-on-one meetings with voting IOC members.
It is probably the biggest persuasion-by-charisma campaign ever undertaken in the Olympic movement.
The Obama factor may be Chicago's trump card but that does not mean the Windy City's three rivals are giving up the ghost.
Madrid claim by sending both King Juan Carlos and Spanish Prime Minister Jose Luis Zapatero they are actually trumping Obama.
Tokyo have newly elected Prime Minister Yukio Hatoyama flying in late on Thursday to join their bid team and Rio think they have charisma to spare by bringing in Brazilian President Luis Inacio Lula da Silva.