some of them a bit hard to back up. >> we have people across this country who are scared to death. >> in the wake of the largest terror attack on u.s. soil since 9/11, the republican presidential candidates delivered tough talk on national security. >> this president hasn't kept us safe. >> still their command of some of the defense topics was, well, up for debate. senator ted cruz has said he would launch an indiscriminate bombing campaign against isis, a tactic known as carpet bombing. as opposed to the surgical strikes the u.s. currently uses. >> would you carpet bomb raqqah, the isis capital where there are a lot of civilians, yes or no? >> you would carpet bomb where isis is, not a city, but the location of the troops. you use air power directed and you have embedded special forces to direct the air power. >> but directed strikes, as he calls them, are the opposite of carpet bombing. >> we need a president -- >> reporter: the senator also blamed the obama administration for not identifying social media