The eyes of the political world will be on the Reagan Library in Simi Valley, California on Wednesday night as eight Republican presidential candidates gather for the third major debate of the contest.

Republican presidential candidate Texas Gov. Rick Perry arrives for a Republican presidential debate at the Reagan Library Wednesday, Sept. 7, 2011, in Simi Valley, Calif. (AP Photo/Chris Carlson) (Chris Carlson/AP)

But, Perry’s performance is far from the only interesting storyline at play in tonight’s proceedings.

Below is our viewer’s guide for the festivities. Check it out. And then don’t forget to tune in at 8 p.m. Eastern time for our live-blog of the debate.

* Perry’s low bar: The coverage leading up to the debate — including in this space — has focused almost entirely on Perry’s relative dearth of debating experience. And, to the extent that the stories have analyzed the debating Perry has done, they’ve portrayed him as a mediocre debater who rarely shines but also infrequently scuffles. All of that is to the good as far as Perry and his political team is concerned since it sets expectations decidedly low for the Texas governor. That’s not to say Perry won’t have challenges — he will be on the receiving end of most of the rhetorical jabs thrown by his opponents and will be a focal point of the debate moderators as well — but that his path to declaring a victory in tonight’s proceedings is relatively uncluttered. Look like you belong on the stage and don’t make any big gaffes. Pretty simple — in theory.

* A different Mitt?: Former Massachusetts governor Mitt Romney has sailed through the first two debates of the primary season — we declared him a “winner” after each one — thanks to a disciplined message focused on President Obama and a commitment to avoiding the barbs directed at him by his Republican opponents. But, coasting is no longer an option for Romney due to Perry’s rise.

The question is whether Romney goes directly after Perry or hopes other candidates do most of the dirty work — allowing him to disseminate the negative information about his opponent without him getting splattered with the mud. One thing to watch: When Romney went on the attack against Sen. John McCain (Ariz.) during the 2008 presidential debates, the other men on stage jumped to McCain’s defense — perhaps as much a reflection of their disdain for Romney as admiration for McCain.

Attacking in a debate is like running back a kickoff in football; you can’t always see where the big hit is going to come from.

* Michele vs Ron: Judging by the new polls from the Washington Post/ABC News and NBC/ Wall Street Journal, it’s Texas Rep. Ron Paul not Minnesota Rep. Michele Bachmann who is sitting in third place at the moment.

Will Paul get treated like a top-tier candidate in terms of the number of questions directed his way and the moderators’ willingness to include him in the big confrontations of the night? Or will he be treated, as he has been at virtually every debate since he began running for president four years ago, like an amusing sideshow? (Make sure to check out our piece on how Paul should be treated in the race.)

If Paul does get more serious treatment that likely means a reduced role for Bachmann who was a centerpiece of the last debate in Iowa in August. (Debates are a zero-sum game; there’s only 105 minutes to be parceled out, so giving Paul more time means taking time from someone else.) Bachmann badly needs a strong performance to re-ignite a faltering campaign and to give that sort of showing she needs time to make her case. She might not get it.

* The peanut gallery: Yes, Perry, Romney, Bachmann and Paul — in something close to that order — will get the most questions and speaking time tonight. But, there will be four other people on the stage looking to make a mark too.

If the last debate is any indication, the one to watch is former House Speaker Newt Gingrich who, freed from any realistic possibility of winning the Republican nomination, has spent the last few months saying whatever he thinks on every topic. (He’s like the Bulworth of the race.) Gingrich’s debating style is argumentative — watch how many times he takes issue with the questions asked of him — and he isn’t afraid to take a major swing at one of his opponents.

If Gingrich, former senator Rick Santorum (Pa.) or former Utah governor Jon Huntsman decide to make it their mission to take Perry or Romney down a peg tonight, it could complicate the two favorites’ calculations. On the one hand, punching down is never a good idea in politics. On the other, if Gingrich/Santorum/Huntsman start the bashing and it’s picked up by the other candidates, Perry or Romney could have a problem on their hands.

* The beginning, the end: The debate is scheduled to last for an hour and 45 minutes — it’s better than two hours but still too long, wethinks — but, in truth, the first 30 minutes and the last 15 minutes are probably what truly matter. While people like us (read: giant nerds) will watch every minute of the debate — heck we might even tape it and re-watch it — most people will tune in for the beginning and/or the end. (In between they will watch “America’s Got Talent”.) Candidates who either start or finish strong, therefore, will be rewarded. Doing well between 8:30 pm and 9:30 pm is all well and good but may not ultimately matter as much as getting off to a strong start or closing on a high note.

* Whither social issues?: Given that polling suggests that even self-identified social conservatives are heavily focused on the economy, it will be interesting to see how much of the domestic policy portion of the debate is dedicated to things like abortion and gay marriage. The likes of Bachmann and Santorum have to hope there is a heavy focus on social issues while Romney and, to a lesser extent, Perry are rooting for a conversation dominated by economy and jobs talk. (Perry’s 2007 decision to issue an executive order mandating vaccines for the human papillomavirus is viewed as anathema by social conservatives.) Also remember that independents tend to be less motivated by hot-button social issues so the more time the Republican candidates spend talking about abortion and gay marriage the worse for them come next November.

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