Republican candidates in the race will appear. It has been reported that Gary Johnson, the former governor of New Mexico, may also qualify for an invitation to the debate. Johnson participated in the debate on May 5th, but has not been invited back since, due to his low poll numbers. If Johnson is able to attend the debate, it will be a result of a quirk in the invitation standards. Elephant Watcher has previously written about the debate admission requirements and how they can lead to unintended invitations.
Johnson was never added to the Elephant Watcher roster of candidates; since Johnson is unlikely to be invited to future debates, and since he has so little support that he's rarely included as an option by pollsters, there is no reason to include him. Including Johnson, there will be nine candidates at the Fox debate. With numbers this large, and with the media perception that the race is essentially Rick Perry vs. Mitt Romney, the debate moderaters will be tempted to give unequal time. Thus far, they have addressed the issue by giving candidates an equal number of questions, but allowing candidates who are mentioned in other candidates' responses to have some rebuttal time. The assumption is that only important candidates (and perhaps only the frontrunner) will be directly attacked, thus giving important candidates extra time without any provable bias on the part of the debate moderators.
The debate tomorrow evening, the third for Rick Perry, will be a defining moment. Perry has attended two debates and has suffered in both of them. If Perry loses ground in yet another debate, there will be two important results. First, it will provide strong evidence that Perry is simply a very poor debater. If so, Perry will continue to lose ground at the many future debates, and grievous harm will be inflicted upon his campaign. Second, it will suggest to voters that Perry is a poor candidate. That perception, even without Perry having yet performed badly at future debates, will do immediate damage. In other words, tomorrow's debate will be Perry's last chance to prove he can escape from a debate unscathed.
For Mitt Romney, the debate will be an interesting test of whether debate moderators and other candidates will continue to attack him on Romneycare. So far, Romney has attended four debates, and Romneycare was brought up at all four--to little effect. If Romney is not asked about Romneycare, it may indicate the issue is losing steam. That would be a very good sign for Romney.
Finally, the debate will be worth watching to see if attacks against Perry's conservative credentials are repeated. In the first debate this month, Michele Bachmann inexplicably gave Perry a pass. But in the second debate, Bachmann joined with Rick Santorum and Ron Paul in attacking Perry's record (on the HPV vaccine and illegal immigration in particular). Will they recognize how effective their attacks were, and intensify them tomorrow? Probably. And this will form a pattern.
Meanwhile, Romney's best strategy will be to build himself up rather than attacking Perry's electability. Romney should stand back and appear presidential allowing Bachmann & Company to attack Perry's conservatism. Romney and his advisors have so far responded to poll numbers in robotic fashion, however, unthinkingly attacking Perry because he is ahead in national polls.
For the minor candidates (those not close to winning any early states, i.e. candidates other than Perry, Romney, or Bachmann), tomorrow will be one of a dwindling number of chances they have to break out of the pack.