Thursday night's Republican presidential debate in Sioux City, Iowa, "will be the final episode in one of the most popular reality television series of 2011," say Peter Hamby and Paul Steinhauser in CNN, and "the stakes could not be higher for all involved." After this face-off between the remaining seven GOP presidential contenders, most voters will tune out until Jan. 3, when the Iowa caucuses launch the actual vote-counting phase of what's already been a long and grueling campaign. What can we expect from this "critical" Fox News/Iowa GOP debate?

1. This will be the last debate for some of the candidates
"If first impressions matter in politics — and they do — so too does the last thing voters see before casting a vote," GOP strategist Doug Heye tells CNN. At least half of Iowa caucus-goers are still undecided, giving everyone a strong incentive to shine. That's especially critical for the low-polling candidates — Michele Bachmann, Rick Santorum, and to a lesser extent Rick Perry — who have staked their campaigns on a strong finish in Iowa. When the next debate rolls around Jan. 7, "the GOP field will undoubtedly be smaller," says Catalina Camia in USA Today. This debate will help determine "who stays and who goes."

2. Romney will try to knock Gingrich out
"Expect Mitt Romney, in his elegant way, to slice Newt Gingrich to pieces," Republican strategist Alex Castellanos tells CNN. Romney doesn't have to win Iowa, but if he can keep Gingrich from coming out on top, "his last serious opponent will be dead and stored in a freezer." As the acknowledged and self-proclaimed frontrunner, Gingrich "has the most at stake when the bantering begins tonight," says Bret Hayworth in the Sioux City Journal, but "Romney has the most to gain."

3. Everyone else will be gunning for Gingrich, too
"Frankly, Romney would be more than happy to see Reps. Ron Paul (Texas) or Bachmann (Minn.) have a good night," says Jennifer Rubin in The Washington Post. Paul especially, since he has a real shot at winning Iowa, and Romney wants him to. But "the more votes Gingrich loses, the better for everyone else," so with all his rivals "trying to provoke and skewer him," Gingrich had better turn in "a steady and uneventful performance." He "can't afford to lose his cool," agrees CNN's Castellanos. "If Newt does his 'angry badger' impression, he will be finished."

4. Someone will have an "oops" moment
"Expect to see at least one candidate make a significant mistake," says the Sioux City Journal's Hayworth, something like Romney's $10,000 bet or Perry's brain freeze. "But don't expect to learn much more about where the candidates stand on the issues." The format of the debate is definitely skewed toward forcing "an oops moment," says Iowa State political science professor Steffen Schmidt. "That's been the biggest news from almost all these debates — who is gonna slip on the banana peel." Everyone will be waiting for, or trying to cause, those pratfalls.