He did seem to fade a bit once the second debate entered hour seven or whatever it ended up being.

Or maybe this is strategic.

Several campaigns are unhappy with the criteria that has been set by CNBC, including the lack of opening and closing statements, and, as of now, the lack of a set length of time for the Oct. 28 debate at the Coors Events Center in Boulder, Colo., according to those briefed…

[Trump campaign manager Corey] Lewandowski, in an interview, said: “The criteria that was outlined by CNBC was never discussed with any of the candidates or the campaigns. So what CNBC did was send out a memo and said, ‘Here’s the criteria as you have approved them and that went out to all the campaigns. We said we never agreed to this criteria.’”…

“For us it was imperative that the time be changed to 120 minutes” for the length of the debate, he said. Mr. Trump had been unhappy with the nearly three-hour length of the CNN debate that Republicans recently took part in.

“Until we have this criteria specifically laid out,” he added, “it is difficult to participate.”

Trump himself pitched in on Twitter after that NYT story was published:

https://twitter.com/realDonaldTrump/status/654729471660941312
https://twitter.com/realDonaldTrump/status/654729649126162432
https://twitter.com/realDonaldTrump/status/654729850721202181

The sticking point for the other campaigns, per Politico, isn’t the length of the debate, it’s the absence of opening and closing statements. Which makes sense: For everyone except Trump, the chief virtue of these periodic cable-news pageants is getting a few minutes to deliver their core message to a giant audience. Trump’s core message is “Trump is awesome,” which he’s been delivering to the public for 30 years. They’ve absorbed it by now. No need to rehash.

As for the length, I’d guess that the other campaigns are quietly fine with the debate running for as long as CNBC wants to keep it going for the simple reason that the longer it goes, the more chances they’ll have to speak. Again, that’s not a problem for Trump, who can get 30 minutes of cable-news time to riff on whatever he wants anytime he wants simply by dialing up CNN or whoever and asking to be put on the air. On the contrary: Both as the frontrunner and as a guy whose grasp of policy detail is not, shall we say, his chief selling point, he has every incentive at this point to keep the debates as short as possible. The longer they go, the greater the risk that he’ll end up in a colloquy on some arcane subject with Ted Cruz, say, and it’ll become glaringly apparent that Cruz knows the issue inside and out while Trump does not. Because Trump’s in the lead in all the polls, he’s playing a defensive game right now, and defense calls for giving the other team(s) the fewest possible opportunities to score. That means a short debate. We’ll see how eager CNBC is to forfeit millions in ad revenue that they’d make from shrinking the debate to accommodate Trump if the alternative is losing him altogether.

In terms of the bigger picture here, Jeff Blehar, one of Ace’s co-bloggers, made a smart point on Twitter last night: The entire arrangement of this year’s debates has backfired ferociously on the Republican establishment. By the end of October 2011, eight Republican debates had already been held with 12 more(!) still to come. This year we’ll end up having just four in the same period (if you include the candidate forum in New Hampshire at the beginning of August) with eight or fewer, depending on how the race shapes up, still scheduled. That was a deliberate decision by the RNC to try to favor establishment candidates. The fear this year was that if they forced someone like Jeb Bush to endure 20 debates, that’d be 20 different opportunities for a Ron-Paul-like insurgent candidate — e.g., Ted Cruz, Rand Paul, etc — to have a breakout moment that would propel them into contention. So they decided to play defense by limiting the number of debates, thus also limiting the right’s chances to make a splash on the big stage. In reality, the opposite happened: It’s Trump, the insurgent, who’s out to a sturdy lead and now it’s the establishmentarians like Bush and Marco Rubio who are desperate for more debate opportunities to try to siphon off votes from Trump. The RNC would have been better off, notes Blehar, with a short debate schedule in 2012, when Romney faced no truly formidable challengers, and a longer schedule this year, when there’s a much bigger field with lots of strong contenders who deserve face time with America. They fought the last war and lost. And now Trump’s taking advantage.

Only two times @realDonaldTrump's seen his poll numbers decline is after the two debates. So of course he's scared. http://t.co/8jkNNnLVHv

— Nate Silver (@NateSilver538) October 15, 2015

Update: Can’t find anything to confirm this yet, but this is how I’d bet if I were a betting man:

@realDonaldTrump wins again: ppl inside @CNBC say network will cave to his debate demands because ads sold based on Trumped-up audience size

— Charles Gasparino (@CGasparino) October 15, 2015

If CNBC’s choices are between an enormous audience for two hours with Trump and a mediocre audience for three hours without Trump, the choice is pretty clear.