As we come on the air, president obama and republican presidential candidate mitt romney are in a duel over war and peace. 43 days before "your voice, your vote" the question is this, how does the... See More
As we come on the air, president obama and republican presidential candidate mitt romney are in a duel over war and peace. 43 days before "your voice, your vote" the question is this, how does the united states stop iran from getting a nuclear weapon and taunting both of the candidates from the sidelines, the president of iran, mahmoud ahmadinejad is in new york, he's at the united nation. Also abc's barbara walters will be here because she spoke with the president and mrs. Obama but first, abc white house correspondent jake tapper at the united nations with what happened there. Jake. Reporter: Good evening, diane. Today's political back and forth represents the highest of stakes with president obama coming to the united nations meeting with leaders for the annual meeting of the general assembly. As president obama arrived in new york city today, mitt romney is focused on comments the president made to "60 minutes" about whether the recent events in the islam world gave the president pause about the arab spring movement. The president said no. I'm sure there will be bumps in the road. Reporter: In pueblo, colorado the e republican nominee down played the president. He said the phelps in the middle east were bumps in the road. Yeah, that was my reaction. Bumps in the road. We had an ambassador assassinated. Reporter: The president was referring to changes in the region. There's a certain attempt to grasp words and phrases to find political advantage and in this case that's profoundly the case. Reporter: This comes before an intentionally serious international back drop not just unrest in the muslim world but iran's chemical threat to its ally, israel. Ahmadinejad signed a peace sign but they said if the jewish state poised to attack? The unthinkable dilemma who if iran attacked or threatened israel or israel preemptively attacked iran. Romney is using the many challenges in the region to paint the president as weak. Look at are entire context. Assassination, 20,000 people killed in syria. These are far from bumps in the road. Reporter: The president responded with a challenge of his own. If he suggests we should start another war. We should say so. Reporter: Foreman they'll address the u.N. Assembly.
This transcript has been automatically generated and may not be 100% accurate.