but only donald trump raised his. >> mr. trump -- >> reporter: refusing to commit that he won't run as an independent. >> you can't say tonight you can make that pledge. >> reporter: rand paul pounced. >> he is used to buying politicians. >> reporter: a combative trump tangoed with moderators. >> you call women you don't like fat pigs dogs slobs and disgusting animals. >> only rosy o'donnell. i think the big problem this country has is being politically correct. >> reporter: try explaining that to your kids. jeb bush dismissed trump as a divisive figure. >> we will win when we unite people with a hopeful optimistic message. >> donald trump is hitting a nerve in this country. people are frustrated. they are fed up. he has his solutions. some of us have other solutions.