As with anything in life, the conventional wisdom is that those sitting at the top of the GOP field have the most to lose with the first debate.
If Donald Trump doesn't give real details about policy plans or if he suddenly decides to play it safe and not tell it like it is -- he may lose some ground. The same is true for Jeb Bush. If he doesn't knock it out of the park with fire in his belly and show some political passion -- and define himself as a different Bush after the two before him -- he could risk losing his current second place position. On the other hand, Trump because he's not a politician could speak to the issues in a simpler way and elevate his poll positioning even more.
It's interesting to note the happy hour candidates probably have the least to lose. By being separated from the pack -- it gives them a chance to shine on their own - away from the top 10 focus.
Whatever the case, the first GOP debate is the official beginning of the 2016 presidential race -- I hope you will be engaged and as always -- let me know your thoughts.