This combination made with file photos shows, from left, President Barack Obama, Iranian President Hasan Rouhani, Syrian President Bashar Assad, and Russian President Vladimir Putin. 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. AP File Photos 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. It begins with the U.N. Security Council scrambling to put together a resolution that is sweeping enough to ensure that Syrian President Bashar Assad surrenders all his chemical arms, and with sufficient penalties to discourage him from reneging. The five permanent members of the Security Council - the U.S., Russia, China, Britain and France - all hold veto power, and Russia has not shied from blocking a council resolution that would punish Syrian behavior in the civil war. The Russians were especially vigorous in promising to veto air strikes to punish Syria for the Aug. 21 chemical attack that killed hundreds of people in a Damascus suburb. The U.S. blames Assad's regime for the attack; Russia says there is no proof that the regime was responsible and suggests it may have been the rebels who carried it out. Lacking U.N. approval, U.S. President Barack Obama - who had warned last year that Assad's use of chemical weapons would cross a "red line" - was nevertheless about to wage a limited air offensive against Syria but pulled up short and sought U.S. congressional approval. It then quickly became clear that Obama would not get that backing, with polls showing the American public solidly against any further military involvement in the Middle East. At that point, Russian President Vladimir Putin stepped in and strong-armed Assad into agreeing to turn over his chemical arsenal to international control and destruction. Obama, faced with the prospect of attacking Syria against the will of both the U.S. Congress and the U.N. Security Council, jumped to accept the Russian gambit. Putin has put himself on the line. This was not done lightly. This was not done to embarrass Obama," said Stephen Cohen, professor emeritus at New York University. This was done for what Putin and (Foreign Minister Sergey) Lavrov think is Russia's national interest. James Collins, of the Carnegie Endowment for International Peace and a former U.S. ambassador to Moscow, offered a similar assessment. "Putin has put his neck way out in terms of responsibility for seeing this happen," he said. "If the Americans can resist the idea they have to micromanage everything and have it done only our way," the Russians will force Assad to rid himself of chemical weapons. Washington contends that the Russians jumped in with their plan only after Obama pushed military action, a threat the American leader says will remain on the table regardless of the outcome at the United Nations. As a result, Obama will probably not insist that the coming U.N. resolution on Syrian chemical disarmament include such a threat should Assad fail to live up to the deal. The Russians would balk at anything stiffer than sanctions anyway. And it will be impossible to deal with Syria without at least acknowledging Iranian interests. Tehran has big stakes in backing Assad, who rules Syria as a member of the minority Alawite sect that has close ties to the Shiite Islam of Iran's ruling clergy. Iran's Revolutionary Guard and Lebanese Hezbollah fighters are helping Syrian government troops in their war against a diverse group of rebels, who appear increasingly dominated by al-Qaida-linked jihadists. Iran provides Assad with military and financial aid and uses him as a counterweight to powerful Sunni Muslim regimes in Saudi Arabia and Egypt that dominate the Middle East. Iran's deep historic ties with Syria and the election of new President Hasan Rouhani puts the Islamic Republic under a bright light during the U.N. General Assembly, particularly because of his moderate statements and exchange of letters with Obama. That has raised hopes of renewed talks on Tehran's nuclear ambitions. Tehran insists its nuclear program is peaceful and that it is enriching uranium to levels needed for medical isotopes and reactor fuel. Distrust of the Iranians has led the United States, with wide agreement from key allies and even Russia and China, to impose economically crippling sanctions on Tehran. Rouhani is determined to work his way from under the damaging penalties and has suggested he's ready to deal and has the authority to do so from the country's supreme leader, Ayatollah Ali Khamenei. Any direct exchange between Obama and Rouhani at the United Nations would be largely symbolic, with substantive negotiations on Iran's nuclear program almost certainly reserved for later talks with officials from both governments. But with that carrot hanging in front of both the U.S. and Iran, Tehran also is likely to have a significant, if behind-the-scenes, role in wider attempts to end the Syrian civil war. It's possible that Security Council action to disarm Assad of chemical weapons could breathe new life into U.S.-Russian attempts to bring the parties to a peace conference in Geneva. With Russia - Syria's main sponsor for decades - getting tough with Assad, the Iranians could well join in to work toward a settlement. Assad will likely be a winner as well. Tehran, like Washington and Moscow, is frightened of the increasing power of radical Islamist fighters flooding into Syria. The interests of the United States, Russia and Iran, to one degree or another, all point toward heavy pressure on Assad to sign on to an agreement, where his survival is the least bad outcome. The only reason the Russians and Syrians are playing along is to ensure Assad's survival. The idea that this is going to lead to a diplomatic solution that leaves Assad out is just not in the cards. I don't think this process is going to lead to Assad's demise. Quite the contrary," said Robert Satloff, executive director of the Washington Institute for Near East Policy. EDITOR'S NOTE - Steven R. Hurst, The Associated Press' international political writer in Washington, has covered foreign affairs for 35 years, including extended assignments in Russia and the Middle East.