The latest CNN poll shows Donald Trump losing ground from his high of 32 percent back down to 24 percent.

He is still the front runner, but his mean and crude debate performance appears to have put a dent in his invincibility armor. It is early yet, but something like a Trump ceiling is emerging, as voters desperately seeking an outsider shift to Carly Fiorina, whose support among GOP voters jumped from 3 percent in a Sept. 4-8 poll to 15 percent in this latest survey, one point above Ben Carson, who slumped from 19 percent to 14 percent.

Marco Rubio almost quadrupled his support as a result of his debate performance, jumping from 3 percent to 11 percent, leaping in front of Ted Cruz for those who seek a more conventional candidate.

Maggie Gallagher is a senior fellow at American Principles in Action.