Is Russia Using a Nuclear Weapon a Threat to Ukraine?

I think what the Ukrainian people have accomplished is extraordinary and it's a testimony to not just the courage of a few soldiers, but this is a entire nation mobilizing in the face of extraordinary odds. I do think, probably the thing that I'm most concerned about is that lines of communication between the White House and the Kremlin are probably as weak as they have been in a very long time. As we defend democratic values abroad, we defend them here at home.