tens of thousands of russian troops sit along the ukraine border. the u.s. embassy says the shipment includes 200,000 pounds of lethal aid. the pentagon is also working on new military options for the biden administration, should russia invade. sources are telling cnn the u.s. embassy in ukraine has requested authorization from the u.s. state department to evacuate all nonessential staff and their families. cnn's international and diplomatic editor, nic robertson is in moscow for us and cnn's arlette saenz and at the white house. while a diplomatic solution remains possible, how much of this is in vladimir putin's hands? >> yeah, i think the next step is clearly in his hands. what he's waiting for at the moment is a written response from the united states to russia's security proposals, demands as they're seen by nato. he already knows the answer. he knows the answer to putin's question that ukraine should not