the donald. >> before a debate i go out and run. way to relax. can't take phone calls, reading e-mails or looking online. you are out running that clears your mind. >> before a debate i normally call my mom to get advice. hey, mom. i can't say that on television. >> tonight's debates. the one that happened. the main event coming up at 9:00. the first time the 2016 republican presidential candidates have shared a stage. the stakes may not be the same for all of them. that's obvious. so question is who stands to gain and lose the most tonight. i want to dig deeper now with our chief national correspondent john king gloria borger and nina malika henderson. >> donald trump has only emerged stronger is there any scenario under which he actually loses tonight? >> it's possible. he could say something. some of the others might come after him like carly fiorina did