so the threat for europeans and american targets in europe is steadily high. >> yeah, it's extremely challenging. to add what the guest said, you have the sheer volume, the ease of travel with the european passports and visas. and that speaks too that matter of working with allies about staunching the flow. up to this point, over three years with the civil war in syria, it's been quite easy, particularly through turkey. one other alarming -- we have enough alarming aspects at this point, of this situation, we don't have a frame of reference for this really in the west. >> what do you mean? >> well, if you take the fighting, the foreign fighters against the soviets in afghanistan in 1970s or through the 1980s. >> right. >> we didn't have -- we already exceeded the through-put of foreign fighters going into syria and a iraq. we also didn't have the degree of this extreme incukuculcatinc. ion. >> but the technical is incredibly alarming. >> that's right.