Simi Valley, Calif. - What should voters expect to see in Wednesday night's second debate of Republican presidential candidates? The answer has become as unpredictable as the summer's campaign.
"Pointed policy-specific questions and follow-ups? Trump ad hominems? A brawl?" said Doug Muzzio, political science professor at Baruch College.
Experts say the 15 candidates following the red-hot, front-running Donald Trump could focus on his few missteps when pressed on foreign policy. That could be fertile ground for Republicans who know their party's nominee may face Democrat Hillary Clinton, the former secretary of state steeped in foreign policy experience.
The rising star in the group, former CEO Carly Fiorina, will get her first shot in the main event after she rose in the polls after the first debate. She struck back effectively against Trump when he appeared to disparage her looks by saying, "Look at that face. Would anyone vote for that?" She responded so sharply that Trump later said he was misunderstood, and that he was referring to her persona.
The super PAC Carly for America Committee released an ad this week with the faces of several women and with Fiorina saying: "Ladies, look at this face, and look at all of your faces -- the face of leadership."
The candidate in second place in most polls, former neurosurgeon Ben Carson, has in recent days appeared to cement his modus operandi: cool, thoughtful comments with sideswipes at Trump that don't appear as nasty as some of Trump's.
Trump has talked of toning down his rhetoric now that he is trying to establish himself as the party's best choice for president. Some measure of that is likely as Trump tries to avoid a big mistake Wednesday night with 15 candidates and a moderator taking aim, said Professor Meena Bose, the Kalikow chair in presidential studies at Hofstra University and director of its Center for the Study of the American Presidency
Others, such as former New York Gov. George Pataki, face not-so-quiet desperation in this second debate. Pataki is among the second tier candidates polling 1 percent of voters who need to make a jump at least from the not-ready-for-prime-time candidates to get to the big stage, which is expected to be seen again by over 20 million people.
However it's done, the candidates at the Ronald Reagan Presidential Library in this scenic valley of hills will again violate what Reagan called the 11th commandment: "Thou shalt not speak ill of any fellow Republicans."
The CNN debate at the Ronald Reagan Presidential Library in Simi Valley, Calif., begins with the second tier of candidates at 6 p.m., followed by those polling the biggest numbers at 8 p.m. in New York.