NEW YORK -- The United States is prepared to negotiate with "any nation, including Russia and Iran," to solve the ongoing conflict in Syria, US President Barack Obama told the United Nations' General Assembly on Monday.His willingness to engage with the two countries, which are the primary benefactors of embattled Syrian President Bashar Assad, marks a new phase in a longstanding effort to end the four year-old war through diplomatic means. Obama has previously said that Assad, whose army has targeted and killed tens of thousands of civilians, has no role in a future Syria.Over the last two years, the policy of the Obama administration has been to train and equip moderate Syrian rebels fighting for Assad's ouster— an "illegal" endeavor, Russian President Vladimir Putin said this weekend. The Pentagon says only 60-odd fighters have been successfully trained in the multi-million dollar program; Five have deployed, and the rest have fled with US weapons to join Islamic State.Moscow and Tehran say Assad is the only legitimate leader of the Syrian people. Their support for his government, they say, amounts to a a counterterrorism effort, as he battles growing terrorist organizations such as Islamic State and the al Nusra Front."We see some major powers assert themselves in ways that contravene international law," Obama said on Monday. "We see an erosion of the democratic principles and human rights that are fundamental to this institution’s mission; information is strictly controlled, the space for civil society restricted.""We’re told that such retrenchment is required to beat back disorder; that it’s the only way to stamp out terrorism, or prevent foreign meddling," he continued. "In accordance with this logic, we should support tyrants like Bashar Assad, who drops barrel bombs to massacre innocent children, because the alternative is surely worse."Obama told the assembly hall that "realism leads him down the path of compromise— "recognizing that diplomacy is hard," he said; "That the outcomes are sometimes unsatisfying; that it's rarely politically popular." But "to move forward in this new era," he continued, "we have to be able to acknowledge when what you're doing is not working."Obama called out Assad by name for his practice of dropping barrel bombs on "innocent children," and noted his use of chemical weapons in August of 2013 in the Damascus suburb of Ghouta. The attack killed nearly 1400 people, roughly 500 of whom were children, according to US intelligence findings.The war has led to a refugee crisis in Europe that has now reached "an epic scale," Obama said. The president committed to opening US borders to more refugees in the years to come.In previous addresses to the UN, Obama has outlined a policy of multilateralism— the use of international bodies to reinforce global, liberal standards and norms. That doctrine, he said on Monday, proved effective in his pursuit of a peaceful solution to the dispute with Iran over its nuclear program."Nations succeed when they pursue an inclusive peace," he said. Such a path, he continued, is "now available" to Iran, after it had agreed to the Joint Comprehensive Plan of Action this past summer.But such a path will require Tehran to turn away from its habit of deploying "violent proxies" in pursuit of its regional aims, he said, which "fuel sectarian conflict that endangers the entire region, and isolates Iran from the promise of trade and commerce." And while he is prepared to compromise with Iran on Syria, he says that a pre-war scenario— in which Assad remains in power, after "slaughtering tens of thousands of his own people"— is untenable."The United States is prepared to work with any nation, including Russia and Iran, to resolve the conflict. But we must recognize that there cannot be, after so much bloodshed, so much carnage, a return to the pre-war status quo," Obama said."Yes, realism dictates that compromise will be required to end the fighting and ultimately stamp out ISIL," he continued. "But realism also requires a managed transition away from Assad and to a new leader, and an inclusive government that recognizes there must be an end to this chaos so that the Syrian people can begin to rebuild." Addressing the body on its 70th anniversary, Obama attacked illiberal systems of government, "strongmen" and the practices of dictators as an "old way" of government best kept in the past. But he also asserted his will to negotiate with strongmen, and characterized that policy as a sign of American strength.In his speech to the UN in 2013, Obama outlined what were then his primary foreign policy goals: "In the near term," he said, "America’s diplomatic efforts will focus on two particular issues: Iran’s pursuit of nuclear weapons, and the Arab-Israeli conflict.""While these issues are not the cause of all the region’s problems, they have been a major source of instability for far too long, and resolving them can help serve as a foundation for a broader peace," he continued.Since that time, Obama's secretary of state, John Kerry, has pursued diplomatic initiatives on both fronts. A nine-month peace process brokered by Kerry between Israel and the Palestinians failed to produce results, but a deal capping Iran's nuclear program for fifteen years was agreed upon in July of this year.The next year, in 2014, Obama placed some blame for that diplomatic failure on the withering will of the Israeli public. Violence engulfing the Middle East has made “too many Israelis ready to abandon the hard work of peace,” he said. "That’s something worthy of reflection, within Israel."Obama made no mention of Israel or the Palestinians in this year's speech.