to execute. >> just before i let you go here, a quick note from one of our folks here at cnn, who is a law enforcement expert, says no-fly zone, terrible idea, leads to world war iii, u.s. shoots down a russian jet, world war iii. what do you think of that? >> well, chances are, it wouldn't go that far, depending on who is on that jet. remember we had the incident with the mh-17, malaysian airliner shot down over eastern ukraine, at the beginning of this whole episode in 2014. that kind of thing results in a lot of tension. it may not result in a war. but there's always the risk that it could. i think it would be a very difficult thing to execute. tensions would possibly increase. and they would have to be managed very, very carefully. >> colonel, thank you very much. learned a lot, as usual. appreciate it. >> you bet, don. ukraine's capital under