RUSSIA - THE world is on tenterhooks over a looming United States-led military strike on Syria, as well as fears that a sudden withdrawal of America's financial stimulus measures could plunge global financial markets into turmoil.
Against this backdrop, the Group of 20 (G-20) summit held here on Thursday and on Friday would offer leaders - who preside over two-thirds of the world's people and account for 90 per cent of its gross domestic product - a chance to get into a huddle and grapple with these collective challenges.
All eyes, however, will be focused especially on US President Barack Obama and his Russian host, President Vladimir Putin. The two men are in desperate need of another "reset" in their relations.
Ties have been strained since Moscow granted asylum to former US spy agency contractor Edward Snowden, prompting Mr Obama to call off a planned bilateral summit.
Russia's thwarting of a consensus at the United Nations for punitive action against Syria, a close Russian ally, has no doubt rankled the US. Mr Putin has dismissed US allegations that Damascus resorted to chemical weapons as "utter nonsense", saying government forces had no need to do so as they were winning the battle against rebels.
The US President, on the other hand, is convinced that the brutish regime of President Bashar al-Assad used toxic sarin gas to kill over 1,400 of his own people.
Still, Mr Obama is loath to be cast as a new George W. Bush, rushing headlong and alone into a costly Middle Eastern adventure. He has lamented that while everyone agrees that the use of that "most heinous weapon" - nerve gas - should not go unpunished, no one wants to do the punishing.
Around the world, many continue to question the intelligence evidence presented so far, haunted by the ghosts of Iraq from a decade ago, with its rush-to-judgment and war, and the sectarian mess that followed.
Still, everyone knows that the incontrovertible evidence that some are demanding may never come amid the usual fog of war. At some point, a difficult judgment will have to be made between the risks of a military strike worsening a longstanding conflict and the dangers of inaction, which would embolden Mr Assad, and dictators from Teheran to Pyongyang.
Given the high stakes, Mr Obama surprised many by pressing the pause button last Saturday, refusing to move before getting approval for a military strike from the US Congress, even though he says he does not need one under the law.
A "no-go" vote would hit not only his standing as US leader at home, but also America's reputation abroad. The much-debated war-making powers of the US presidency will also be called into question.
By holding off on the attack which many were expecting him to launch last weekend, Mr Obama is also putting the challenge to his G-20 counterparts. Syria, he is saying, is not a US problem, but a global one.
G-20 leaders will not be able to simply wring their hands, or tut- tut at Mr Obama for going solo. The world will be watching to see just where they stand collectively on the use of chemical weapons, and how they respond to what US Secretary of State John Kerry has dramatically dubbed a "Munich moment", referring to the appeasement of Hitler in the 1930s.
So, the Syrian question is likely to feature during the leaders' discussions, even though it is not officially on the agenda. The hosts of the two-day summit have planned several working sessions on issues related to economic growth and inclusive development, as well as efforts to boost job creation.
These come amid widespread talk of "Septaper", the term used by investors to refer to the US Federal Reserve's plans to begin tapering its massive bond purchases later this month, in line with a faster growing domestic economy.