Five things to watch as Republicans take the Las Vegas debate stage

Nine Republican presidential hopefuls will gather Tuesday night on a stage in Las Vegas for their fifth and final debate of 2015. We hereby foreswear any Sin City allusions or obvious gambling metaphors.

No doubling down, no rolling of dice, no high-stakes confrontation, no jokers in the deck.

Instead, here are five things to watch for as the candidates face their last chance to pitch themselves to a national audience before the full force of the holiday season diverts all but the most obsessive political observers.

-- This entire campaign season has moved like a circle around Donald Trump’s little pinkie, and Tuesday night may be no different. So which Trump shows up at the Venetian resort, passive or aggressive? He’s been both in previous onstage encounters.

Little that Trump says or does will likely matter to his supporters, who don’t seem to budge for any reason. But the positions Trump takes and, especially, the tone and rhetoric he uses will force other candidates to either respond or ignore him and allow the bombastic billionaire to stand unchallenged as the leading voice of the GOP.

-- The ascendant Ted Cruz will enjoy a more prominent spot onstage, right next to Trump. That reflects the Texas senator’s rise in national polls and his new front-runner status in Iowa, the first state to vote. He will probably face much tougher scrutiny, from both the moderators and his fellow candidates, than in previous debates.

After strenuously avoiding conflict with Trump, hoping to scoop up his supporters should he falter, Cruz was caught on tape privately bad-mouthing his rival, who responded in characteristic fashion with a litany of insults.

Cruz may also face attacks from Florida Sen. Marco Rubio, who has been climbing in polls and, not coincidentally, recently started assailing Cruz as weak on defense and fighting terrorism. The question is whether Cruz, whose antagonism has inspired a deep loathing in both parties, can parry the assault without appearing even more disagreeable.

-- Chris Christie returns to the main stage after being relegated to the kids’ table in the last debate. New Jersey’s governor has gained traction in New Hampshire, which holds the first primary eight days after Iowa starts the nominating process with its Feb. 1 precinct caucuses.

He’s been a strong performer in previous debates, when rivals have mostly left him alone, figuring Christie was not much of a factor. Will that change, now that he’s suddenly relevant, and how will the in-your-face Christie react?

-- Jeb Bush, son of the nation’s 41st president, brother of the 43rd, a former 800-pound gorilla shrunken to the frail physique of a political weakling, has faced supposed do-or-die circumstances in each of the last several debates. By most accounts, the former Florida governor proved greatly underwhelming.

Still, he lives and breathes. That said, is there anything he can say or do to revive his campaign and end the political death watch?

-- How assertive will CNN’s co-moderators, Wolf Blitzer and Dana Bash, be in their questioning? (The two will be joined onstage by conservative talk radio host Hugh Hewitt.)

The panelists from CNBC were roundly criticized (and not just by Republicans) for their aggressive, sometimes impertinent performance at an October debate.

The gentler questioning at a Fox Business/Wall Street Journal debate two weeks later was far more to the liking of the candidates and Republican Party leaders, but often proved less than edifying on the differences among the candidates, or the superficiality of some of their positions.

Will CNN’s hosts manage a better balance?

mark.barabak@latimes.comFollow

Follow @markzbarabak for national and California politics.

ALSO

Punches fly as demonstrators get kicked out of Trump rally

National security concerns appear likely to color Republican debate

Twin paths of Rubio and Cruz end at their political perspectives