"I think everybody understands ... that I want to reduce nuclear stockpiles. And one of the barriers to doing that is building trust and cooperation around missile defense issues," Obama said in Seoul a day after an open microphone picked up a private conversation in which he told outgoing Russian President Dmitry Medvedev he would have more room to negotiate about the shield after the November presidential election.
"And so this is not a matter of hiding the ball," Obama said. "I'm on record."
The president said he had said essentially the same thing in speech Monday at South Korea's Hankuk University of Foreign Studies. He did not address the fact that he still had to win the general election Nov. 6 to have meaningful discussions with Moscow afterward.
Washington and NATO say the missile shield would protect Western nations from missile attacks from possible nuclear powers such as North Korea and Iran. Moscow says the shield could weaken its own nuclear capabilities and proposes collaborating on a joint system.
On Monday, Obama was heard telling Medvedev: "This is my last election. After my election, I have more flexibility."
"I understand," Medvedev said. "I will transmit this information to Vladimir," a transcript provided by ABC News indicated.
"Vladimir" referred to Russian Prime Minister Vladimir Putin, who won another term as president this month and is to be inaugurated May 7.
Putin promised to appoint Medvedev prime minister, but that is not guaranteed.
Obama told reporters Tuesday he intended to spend the rest of the year working through technical issues with the Russians.
"Arms control is extraordinarily complex, very technical, and the only way it gets done is if you can consult and build a strong understanding, both between countries and within countries," Obama said.
So he said he did not consider it startling that working out a deal takes time, especially during an election year in both countries.
"I don't think it's any surprise that you can't start that a few months before presidential and congressional elections in the United States, and at a time when they just completed elections in Russia, and they're in the process of a presidential transition where a new president's going to be coming in, in a little less than two months," he said.
Obama joked about the open-mike incident, saying before talking to reporters, "First of all, are the mikes on?"