ukraine leaders scrambling to keep the crimea region from slipping further under russian control. correspondent erin mcpike has details on the meeting. interim ukrainian prime minister will travel to the united states to meet with president obama on tuesday. the prime minister has said the vote crimea intends to hold next sunday, a referendum to secede from ukraine and join russia, is illegitimate. president obama and several european leaders agree. what if that referendum is successful a week from now? president obama's deputy national security adviser, tony blanken, was on cnn's "state of the union." he made a declarative statement about how the united states will react. >> if there's a referendum that moves crimea from ukraine to russia we won't recognize it nor will most of the world. >> reporter: former vice