“Honestly, does anyone think I care what Donald Trump thinks about my face?”

And when an older man in New Hampshire told Mrs. Fiorina that Mr. Trump was wrong about her appearance, she said, “Honestly, does anyone think I care what Donald Trump thinks about my face?”…

Just her presence on the CNN prime-time stage could signal to voters her willingness to take on the establishment. Mrs. Fiorina’s recent uptick in the polls—along with her campaign’s forceful push to change the debate’s rules—compelled CNN to alter its criteria and qualify her for the main event.

The debate’s focus on foreign policy will play to the strengths of Mrs. Fiorina, who served as chairwoman of the Central Intelligence Agency’s External Advisory Board. She tells voters that she knows more foreign leaders than any other candidate, with the possible exception of Mrs. Clinton. But she says she didn’t do “photo ops”—she did business.

Mrs. Fiorina said in an interview that she wouldn’t do any mock debates to practice. Before she takes the stage, she will read and study the issues, play a little solitaire on her phone, spend some time with her husband and say a prayer.