communication line which is designed to do just that. they don't want to see any direct conflict with the u.s. over the skies in syria which this de-confliction line it's called were designed to prevent. at the same time, you have a very different situation to what happened last time that line was severed. now you have pro-regime assad forces moving toward raqqah as they're trying to push isis out of raqqah. they all have a view to the post-isis carve-up of southeeas syria. there's a question of how much control the kremlin has over assad's forces. whether as the u.s. said you need to calm down the situation, whether the kremlin would be able to. of course, you have iran also flicksing -- flexing its muscles on the border sending in ballistic missiles over the weekend. it is a very, very volatile situation. and it is one that russia, too, knows that it is better to talk rather than threaten the united states about.