All the world gets a stage at U.N. General Assembly UNITED NATIONS (Reuters) - Here is what the U.N. General Assembly next week will not achieve: ending Syria's civil war, easing Muslim protests over insults to Islam and grinding Iran's nuclear program to a halt. But the world's most pressing, and intractable, problems will be on display as leaders and their entourages from the 193-nation assembly descend on U.N. headquarters in New York for the world body's annual "general debate" from September 25-October 1. More than 100 heads of state and government are expected to gather at the United Nations for what is traditionally the busiest week of the year for international diplomacy. Last year, U.N. Secretary-General Ban Ki-moon held 119 bilateral meetings with presidents, prime ministers and government ministers from all parts of the globe. Ban said on Wednesday he expects to have more than 120 such meetings this year. While there is no single theme of this year's general debate, he said "the deteriorating situation in Syria will be foremost in our minds." Several senior Western envoys said another theme will be the recent violent unrest in some Muslim countries caused by anger at an anti-Islam film made in the United States and French cartoons denigrating Prophet Mohammad. "The backdrop of Syria, the Arab Spring, the recent unrest, the clash between freedom of expression and defamation of religions - all that will undoubtedly be a theme across all bilaterals and all these side events," one diplomat said. The gathering will shine a spotlight on Syria and other pressing problems facing the planet: insurgencies in Mali and eastern Democratic Republic of the Congo, climate change or global financial woes. Solutions, however, will likely have to wait. The assembly, unlike the 15-nation Security Council which can impose sanctions or authorize military interventions, has virtually no real power. It focuses on public debates and issuing non-binding resolutions that are often ignored. But the gathering of leaders and ministers offers countries a forum to publicly air their grievances on the issues of the day and opportunities for a wide range of bilateral and larger meetings. This year there will be side meetings on violence against women, health, development, Yemen and Myanmar. There will also be meetings on Syria and Iran's nuclear program. But envoys say little of note will happen at those, largely due to a widening chasm between Western powers on the one hand, and Russia and China on the other, a chasm that is preventing the Security Council from taking meaningful action. Moscow and Beijing have used their Security Council veto powers to block three resolutions that would have condemned Syrian President Bashar al-Assad for his 18-month assault on an increasingly militarized opposition determined to oust him. They have also voiced opposition to new sanctions against Tehran. U.S. President Barack Obama, who is in the final months of a re-election campaign, will be stepping up to the podium for the fourth time. He is the second speaker after the General Assembly debate opens on Tuesday, following Brazilian President Dilma Rousseff in Brazil's traditional spot as the first speaker. Israeli Prime Minister Benjamin Netanyahu and Palestinian President Mahmoud Abbas speak almost back-to-back on Thursday. A year after Abbas announced with great fanfare plans to join the United Nations as a full member state - an idea that never had a chance of success because of the U.S. power to veto it - he is expected to reiterate more modest Palestinian plans to push for upgraded membership status at the world body. Obama has no plans to meet Netanyahu, who has been urging the American leader to get tougher on Iran over its nuclear program, though diplomats say Secretary of State Hillary Clinton will meet the Israeli leader and numerous other senior officials from around the world on the sidelines of the General Assembly. Iranian President Mahmoud Ahmadinejad, a regular at the assembly since he took office in 2005, will give his address on Wednesday, which happens to be the Jewish holy day Yom Kippur. He will also address a meeting on the "rule of law" on Monday. In previous years, Ahmadinejad has used his U.N. speeches to defend a nuclear program he insists is peaceful but the West fears is for weapons, and to attack Israel, the United States and Europe. He has questioned the Holocaust and cast doubt on whether 19 hijackers were really responsible for September 11. Western envoys predictably walk out of Ahmadinejad's speeches in protest. The General Assembly has had many memorable moments since it first convened in London in 1946 as the Cold War was emerging from the rubble of World War Two. In 1960, Soviet Premier Nikita Krushchev banged his shoe on a table during an assembly meeting. In the same year, Cuba's Fidel Castro blasted U.S. imperialism for about four hours. Libya's late leader, Muammar Gaddafi, addressed the assembly for the first time in 2009. He spoke for an hour and 35 minutes and managed to touch on subjects ranging from the assassination of U.S. President John F. Kennedy, the U.S. invasion of Grenada and free medicine for the world's children. Venezuela's President Hugo Chavez irked Washington in 2006 when he referred to George W. Bush as "the devil," saying he smelled sulfur around the U.N. podium a day after the U.S. president spoke. Chavez, battling cancer and campaigning for re-election, is not expected to attend this year. Additional reporting by Michelle Nichols; Editing by Doina Chiacu