Evolution, the progression in terms of what the u.s. is willing to provide in terms of weapon systems, the scale of the defense support and how much that's ramped up over the course of the last 11 1/2 months. but so too has the comfort level on the u.s. side with how they're able to assess risks, how they're able to walk through what they believe a russian response will be, and how far they feel they can push things without eliciting the kind of response that would bring this into a much, much more dangerous territory. one thing i would note is a driving force behind that is lines of communica...