3 Republicans To Watch During The Fifth Debate, Because It's The Last GOP Showdown For 2015

On Tuesday, CNN will host the fifth Republican debate of the 2016 cycle. With Wolf Blitzer, Dana Bash, and Hugh Hewitt moderating, this will be the last forum of the year, and for some candidates, it may be the last time they're invited to the debate stage at all. While the GOP field is still so big that the networks have to hold two separate debates to accommodate all of the candidates, the number of contenders has been steadily shrinking, and the top tier of candidates is beginning to solidify. That makes the stakes higher than ever this time around, and in particular, there are three Republicans to watch during the fifth debate.

Of course, every debate has the potential to make or break a candidate. That's one of the best things about debates — in one swoop, a contender can drastically alter the trajectory of the race, for better or worse. You saw this in 2012, when Rick Perry's "oops" moment obliterated his chances of becoming president. During this year's CNBC debate, Marco Rubio single-handedly dealt the death blow to Jeb Bush's campaign.

That's why when you tune into the upcoming CNN debate, keep an eye on these three candidates.

Chris Christie

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This may sound counterintuitive: Despite high hopes, Christie has failed to make any impact whatsoever in the 2016 race. But there are some signs that this may be changing. A new poll shows Christie in second place in New Hampshire, and he recently gained the endorsement of the New Hampshire Union Leader, which has historically given candidates a not-trivial boost in that state.

That said, he's still far from the top tier of candidates, and that's why this debate matters. It's Christie's last chance to perpetuate this momentum before the holiday break. How he goes about doing this is anyone's guess, but we'll find out for certain on Tuesday.

Jeb Bush

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Let's be clear. Bush doesn't have much of a chance of winning the Republican nomination. Despite having a nearly-unlimited chest of money from which to draw, he's still languishing in single-digits in the polls and has been since his campaign began.

But this is precisely why you should keep an eye on him. He has nothing to lose, and when a candidate has nothing to lose, that's when they pull out all the stops. Bush will most likely go on the attack, moreso than he ever has in the past; whether or not he succeeds, it'll surely be entertaining to watch.

Marco Rubio

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Ever since Bush's collapse, a lot of establishment Republicans have been praying for a Rubio surge. So far, Rubio's 2016 strategy has been to lay low, let the other candidates duke it out, and emerge as the last man standing later in the primary. But his failure to break out in the polls, Donald Trump's continued resilience, and the recent surge of Ted Cruz make this plan seem a lot less tenable in the long term.

If he wants to remain in contention, Rubio will have to finally have to get aggressive. This debate will practically force him to alter course and adapt to the new conditions of the campaign — and that, in turn, will show whether he's got what it takes to run a successful general election campaign against Hillary Clinton. Rubio has quite a bit riding on this debate, and he knows it.