The sixth Republican debate will happen tonight, for those keeping score. Technically, though, that should read "debates," as there will be two debates airing this evening, as there have been in the previous five GOP matchups. Which really begs the question of how long we're going to even bother holding double debates, when the contest has quite obviously narrowed to include only viable candidates. At some point, the secondary debate is going to be seen as so pointless (and so devoid of an actual viewing audience) that it will be eliminated altogether. Hopefully, at any rate. After having watched most of these, for me that time could easily be now -- but then again, I'm not a television executive.

People have taken to calling the earlier event the "happy hour debate" or the "undercard debate" if they're feeling charitable, and the "kiddie table debate" if they're feeling snarky. This is truly a "scraping the bottom of the polling barrel" affair, as it consists of those candidates who barely even register in public opinion polling of Republican voters. To date, only one candidate has moved up from the preliminary debate to the main stage -- but tonight, Carly Fiorina is moving back down to the kid's table once again.

The Republican field itself has narrowed significantly, down from an astonishing 17 candidates at the start to a more-manageable 12, after (in chronological order) Rick Perry, Scott Walker, Bobby Jindal, Lindsey Graham, and George Pataki dropped out. One of the remaining candidates appears to only be pretending to run (Jim Gilmore), so only 11 real candidates remain.

Only ten candidates will appear on either stage tonight, though: three in the undercard, and seven for the main event. The odd man out is Rand Paul, who was so annoyed at being cut from the big folks' table that he refused to participate in the preliminary debate altogether. As mentioned, Carly Fiorina also was cut from the big stage tonight, but she'll be debating earlier with Rick Santorum and Mike Huckabee. Then we'll get to the real debate, with (in order of their standings in the polls) Donald Trump, Ted Cruz, Marco Rubio, Ben Carson, Jeb Bush, Chris Christie, and John Kasich.

Sooner or later, of course, nobody -- including television executives -- is going to care about the candidates with no chance whatsoever. Eventually, the main stage is going to shrink even further, too, likely as Kasich gets demoted (and possibly Christie, Bush, and/or Carson). But we'll probably see the same seven in at least the next two debates, if not the next three.

The scheduling is interesting for all three of these. Tonight is roughly two-and-a-half weeks from when Iowa caucuses. The next debate is only a few days from the caucuses, and then the third will happen right before New Hampshire holds its primary election. This means these three debates are make-or-break for those candidates who are struggling to even remain relevant.

Normal people (the non-politically-wonky, in other words) have not been paying much attention to the race, so far. In Iowa and New Hampshire, they pay more attention than the rest of us, as they take their "first in the nation" status fairly seriously. But even in the first two states to vote, many people wait until the very end to firmly make up their minds. There are a lot of undecideds who will be tuning in tonight, but fewer will be undecided by the end. Because the next debate is so close to the actual caucus day, tonight may be even more important (even a stellar debate performance usually takes a bit of time to register with the public).

Tonight's crowd can be broken down into two distinct groups: those with targets on their backs, and those emitting the stench of desperation. In the former category are: Trump, Cruz, and Rubio. In the latter: Carson, Bush, Christie, and Kasich.

Here's my take on what we're going to see tonight, from each candidate:

Donald Trump

Trump will do his Trumptastic thing, as usual. He's always good television, and he knows it. But this time around, he's likely going to focus most of his zingers on one man: Ted Cruz. Cruz is the only one who has even come close to Trump, both in the national polling and (in particular) in Iowa -- where Cruz may actually be holding a lead over The Donald. Trump's already previewed his attack line, which is (of course): "Ted Cruz is a Canadian/Cuban Communist who is probably a secret Catholic." Trump will likely play his normal offhanded-smackdown defense against everyone else, since he is in no way currently threatened by any of their anemic polling numbers.

Ted Cruz

Cruz has likely practiced his own zinger to answer the "birther" charge from Trump (or from the moderators, if Trump doesn't bring it up himself), so look for this to be well-practiced. But Cruz is going to be playing defense on a much bigger issue -- that million-dollar loan he got from Goldman Sachs (where his wife works), that he somehow forgot to disclose while running for his Senate seat. This is problematic for Cruz on a number of different levels. There's the dishonesty of hiding something during an election, of course. But there's an even more fundamental problem for Cruz: his entire campaign is against cronyism, the "Washington cabal" (as he puts it), and the big banks on Wall Street. So he got elected with Wall Street money that flowed to him in his hour of need because his wife has a cushy job with a big financial firm? This truly undermines his fundamental reason for running, so look for all the other candidates to get in some snarky shots on this issue. Cruz will have to fight back against this all night, and he's also indicated that he's now ready to take Trump on directly. The Trump v. Cruz head-to-head battle might be the one with the most fireworks tonight, in other words.

Marco Rubio

Rubio will actually have the biggest target on his back tonight. He may try to get in some jabs at Cruz and Trump, but he'll largely be occupied with parrying thrusts from the four desperate candidates on the stage. The conventional Washington wisdom (not saying I agree with this, just reporting what everyone's thinking, mind you) is that there are three "lanes" to victory in the Republican nomination race -- an "outsider" lane, a "Tea Party" lane, and an "establishment" lane. Trump's obviously the winner of the outsider lane, Cruz has the Tea Party lane sewn up, so that leaves only one lane for the other five candidates. And, currently, Rubio's numbers are far better than anyone else's in this lane. All the desperate candidates have already been targeting their ads at Rubio, in the hopes that by taking him down they'll manage to rise in his place. So even though Trump and Cruz are doing a lot better than Rubio in the polling, he'll be the one with the giant target on his back.

Ben Carson

Ben Carson's biggest fight, as always, is not to take a nap in the middle of the debate. Yep, it'll be Carson v. The Sandman, once again. Heh. Seriously, though, Carson is a dead candidate walking. His numbers have collapsed, his campaign is shedding personnel as the rats stream overboard, and he's even lost his base in Iowa, where he was supposed to be strongest. Carson may be around for a few more debates, but he's already toast, so none of the other candidates will likely even acknowledge his presence on the stage.

Jeb Bush

The flop-sweat off Bush will be the most noticeable tonight. This is truly it for Jebbie -- if he doesn't somehow turn in a stellar performance, he's also toast. And he knows it. Some establishment Republicans are already (very quietly, at least for now) suggesting that the time has come for Bush to gracefully withdraw from the contest to give another establishment candidate (Rubio, most likely) a better chance of taking on the two frontrunners. If Jeb doesn't wow the audience tonight, look for these calls to withdraw to get a lot louder and more public. Jeb's challenge is to take on both Trump and Rubio, and not appear a total weenie while doing so. So far, this sort of performance has eluded him. But, like a trapped animal, he has absolutely nothing left to lose, so he may try some sort of suicide squeeze play tonight. He's right to sweat, because it'll probably flop -- but he has to give it that one last college try. If only for those kind folks who put up that hundred million bucks for him to run on.

Chris Christie

These last two candidates are truly only relevant in New Hampshire, so I'm not going to spend a lot of time on them. Christie is (as always) trying to position himself as the best of two worlds -- he's brash, he's edgy, he insults people to their face! -- but at the same time, he also qualifies as a candidate the establishment wing of the party could live with. But he may hold back tonight and keep his powder dry for the next few debates, which will be more relevant to the New Hampshire electorate.

John Kasich

He's still running? Really? And he's not at the kiddie table? Wow -- who knew?!?

OK, that's it for my pre-debate roundup. Sorry for not posting snap reactions afterwards, but I can really only run that sort of gauntlet once in every week, and I already did so for President Obama's last State Of The Union speech, so this'll have to do for today, folks.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant