process, vladimir putin has known the play book of the west. he was told. if you invade the pipeline deal is off. he's well aware of the reluctance to put troop on the ground and the fear of nuclear escalation. that he put out there. i think the if it crosses over into eu or nato territory, all the arguments that have been used against getting further involved go out the window. and you are seeing a physical presence on the ground and heightening of control of the air space and so on. that would be absolutely impossible to avoid. >> let's hope we don't get there. thanks very much for joining us. u.s. lawmakers are in poland to meet with european officials. will their push to send fighter jets to ukraine be effective? plus. ukraine train system is a reliable mainstay of daily life during peacetime. how rail operators are keeping