very 2016 way, on twitter. donald trump tweeting today at jeb bush, i'm fighting to make sure it doesn't happen again. jeb is too soft. that after bush had tweeted, donald trump talks about foreign policy as though he's still on "the apprentice." at issue, trump's suggest uns that jeb's brother, george w. bush, could have done more as president to prevent the september 11th terror attacks. >> blame him or don't blame him but he was president. the world trade center came down during his rein. >> reporter: delayed trump response to one of jeb bush's most passionate moments at cnn's debate last month. >> such a disaster the last three months that abraham lincoln couldn't have been elect sghed are you know what? as relates to my brother, there's one thing i know for sure, he kept us safe. i don't know if you remember -- >> reporter: trump is now even suggesting he could have stopped the 9/11 hijackers from getting into the u.s. in the first place. >> i'm extremely tough on people coming into this country. i doubt that those people would