U.S. President Barack Obama gestures as he speaks during a joint news conference with South Korean President Park Geun-hye at the Blue House, Friday, April 25, 2014, in Seoul, South Korea. The U.S. and Europe are laying the groundwork to sanction broad sections of Russia's economy if Moscow invades eastern Ukraine, Obama said Friday, even as he acknowledged those sanctions may fail to deter Vladimir Putin. (AP Photo/Carolyn Kaster)