back. i hope you would, too. >> he's going nuclear now. >> the candidates there raising the bar all on their way here, the ronald reagan presidential library in beautiful simi valley, california. right now hours away from finding out which republicans can pole vault their way to the top of field. get it pole vault. cnn republican debate 6:00 p.m. eastern, main stage 8:00 p.m. eastern. this is "the lead," i'm john berman, filling in for jake tapper getting ready for the debate. we're all here to break down the practice film and discuss what we can expect from the debate tomorrow night. but first, we want to get a preview from someone who will be on that stage in a shade under 26 hours, republican presidential candidate and senator from e. kentucky, rand paul joins us by phone.