SEOUL, South Korea - President Obama offered his explanation today for the hot-mic moment that caught him asking the Russian president for "flexibility" and "space" on missile defense until after November's election, saying "this is not a matter of hiding the ball."

"The only way I get this stuff done is if I'm consulting with the Pentagon, with Congress, if I've got bipartisan support and frankly, the current environment is not conducive to those kinds of thoughtful consultations," Obama told reporters following a meeting with Russian President Dmitri Medvedev and President Nursultan Nazarbayev of Kazakhstan. "I think the stories you guys have been writing over the last 24 hours is pretty good evidence of that."

Reporters at the Nuclear Security Summit overheard Obama asking Medvedev Monday to tell incoming President Vladimir Putin "on all these issues, but particularly missile defense, this, this can be solved but it's important for him to give me space."

"This is my last election. After my election I have more flexibility," he added.

Today, Obama stressed that his remarks reflect the political climate.

"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," he said. "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 a little less than two months."

While his conversation with Medvedev was intended to be private, Obama said it was not "a matter of hiding the ball."

"I'm on record," the president said of wanting to reduce nuclear stockpiles. "I want to see us over time gradually, systematically reduce reliance on nuclear weapons."

Obama's comments today came after Republicans pounced on the open-mic incident.

"When the president of the United States is speaking with the leader of Russia saying he can be more flexible after the election, that is an alarming and troubling development," Republican frontrunner Mitt Romney said. "This is no time for our president to be pulling his punches with the American people. And not telling us what he's intending to do with regards to our missile defense system, with regards to our military might and with regards to our commitment to Israel and with regard to our absolute conviction that Iran must have a nuclear weapon."

Obama does seem to have a sense of humor about the incident. Before responding to a reporter's question about his comments, Obama jokingly asked "first of all, are the mics on?"