the ukrainian forces and citizens there are going to make it very, very bloody. and over the course of time that will be a determining factor in terms of how much will the russians have to stick around and carry this thing through. >> we're now hearing about a potentially new threat. the white house has warned russia could use chemical weapons. how could that change the game here in terms of how ukraine fights and nato potentially helps? and how should ukrainians prepare? >> well, it's a war crime. they're not -- they're banned. they're not supposed to be used in combat. weapons of mass destruction are over another category. if they are used, it's ghastly. it can be deadly. the russian forces have to put up with it as well. because if you use chemical weapons now you're trying to occupy a space you've completely contaminated. this continues to pill up all the evidence that's absolutely in front of us that labels putin a war criminal.