President Obama at the UN: Stop Iran from obtaining a nuclear weapon

President Obama today will pledge continued U.S. involvement in the turbulent Middle East and vow that the U.S. will do "what we must" to prevent Iran from obtaining a nuclear weapon.

In remarks to the United Nations General Assembly, Obama will call the attacks in Egypt, Libya and elsewhere "not simply an assault on America. They are also an assault on the very ideals upon which the United Nations was founded."

According to remarks prepared for delivery, Obama will say that if the body of nations is "serious about those ideals, we must speak honestly about the deeper causes of this crisis. Because we face a choice between the forces that would drive us apart, and the hopes we hold in common."

And he'll summon the memory of US Ambassador J. Christopher Stevens, who was killed in the assault on the consulate in Bengazi, Libya, saying "we must affirm that our future will be determined by people like Chris Stevens, and not by his killers. Today, we must declare that this violence and intolerance has no place among our United Nations."

He will also decry the anti-Islamic video that the administration has said is a factor in the riots, saying there "are no words that excuse the killing of innocents. There is no video that justifies an attack on an Embassy. There is no slander that provides an excuse for people to burn a restaurant in Lebanon, or destroy a school in Tunis, or cause death and destruction in Pakistan."

Obama will also say that the U.S. wants to resolve Iran's quest for a nuclear weapon "through diplomacy" and believes "there is still time and space to do so.

"But that time is not unlimited," he is to say. "We respect the right of nations to access peaceful nuclear power, but one of the purposes of the United Nations is to see that we harness that power for peace. Make no mistake: a nuclear-armed Iran is not a challenge that can be contained. It would threaten the elimination of Israel, the security of Gulf nations, and the stability of the global economy. It risks triggering a nuclear-arms race in the region, and the unraveling of the non-proliferation treaty. That is why a coalition of countries is holding the Iranian government accountable. And that is why the United States will do what we must to prevent Iran from obtaining a nuclear weapon."