united states probably has what i would call a trigger line. that if additional advances occur proximate to baghdad, the mek, all the shia fighters who are really showing up in combat to bolster the isf. the united states is going to say that's fine. the challenge with that alisyn is this tactical support now leads to a strategic advance where the real relationship that exists in that part of the world is going to be shia dominance, tehran in terms of its very strong relationship with baghdad, which is not what we want to have. but we have this tactical challenge with isis which is real. >> but, spider does that slow burn strategy work? i mean you just heard in arwa damon's report the scenario whereby they could be knocking on baghdad's door? >> yeah i know. it's very very hard. this is the art of the application of force as opposed to the science. it's calling -- it's what we call trading space for time.