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Cold or hot mic? Obama covers up the microphone

Susan Walsh / AP

President Barack Obama covers the microphone as he arrives at the plenary session of the Nuclear Security Summit at the Coex Center in Seoul, South Korea, Tuesday, March 27, 2012. At left is Kazakh President Nursultan Nazarbayev.

Apparently President Barack Obama is able to joke about the open mic gaffe he made yesterday after he was overheard discussing missile defense with Russian President Dmitry Medvedev.

Cliff Owen / AP

The president's fourth year at the White House in pictures — follow along as it happens.

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