nuclear arms agreement saying russia has been breaking the rules of that treaty for a while. >> russia has jeopardized the united states security interest and we can no longer be restrict bid the treaty while russia violates it. >> joining us know, msnbc nuclear security analyst a. geoff bennett, let me start with you. this is a significant policy move. not a surprising one. we've known this is coming. but today the trump administration is in effect pulling the trigger. >> you're right about that. this is the headline. you have the world's two greatest nuclear powers set to pull out of this crucial grae agreement, the inf treaty. inf stands for intermediate range nuclear forces treaty, and the name explains what it does. the agreement requires the destruction of any land-based cruise missile that can strike within roughly 300 to 3500