CNN CNN Democratic Debate October 14, 2015 06:05:00
>> it's certainly the chaos in the middle east. no doubt about it. it all started with the iraq invasion. >> governor o'malley? >> i believe nuclear iran along with the spread of isil, climate change makes cascading threats worse. >> secretary clinton, the greatest national security threat? >> it has to be continued threat from the spread of nuclear weapons, nuclear material that can fall into the wrong hands. i know the terrorists are constantly speaking it. that's why we have to stay vigilant. also united around the world to prevent that. >> senator sanders. >> the scientific community is te...