crimea. ukraine accuses russia of blocking off parts of the black sea in the naval exercises. the u.s. says the same thing, saying that commercial ships will not be allowed through. they won't be allowed to dock in ukraine. russia does deny that. but, erin, on top of what we hear from president biden about the potential for things to get crazy quickly, we are hearing a lot of concern from top nato leaders, including the british prime minister boris johnson who just today said this is the most dangerous moment in europe's biggest security crisis in decades. erin. >> thank you very much, alex. outfront now republican senator mike rounds of south dakota. he sits on both the senate armed services is and foreign relations committees and steevd a classified briefing on ukraine. senator rounds, i know you are limited with what you can share from the briefing. but based on what you heard and the president telling americans to leave ukraine now, do you believe a russian invasion is more likely than it was a day or