WASHINGTON (AP) — After years of estrangement, the United States and Russia are joined as partners in a bold plan to rid Syria of chemical weapons. More surprising yet, American and Iranian leaders — after an exchange of courteous letters — may meet in New York for the first time since the Islamic revolution swept Iran nearly 35 years ago.

Hopes are unusually high as world leaders gather at the United Nations this week. While the results are far from certain, all players in the delicate diplomacy confronting them in the coming days could even come out winners in a world increasingly fraught with zero-sum outcomes.