Donald Trump didn’t exactly make the debate stage great again. Tuesday’s CNN Facebook Republican presidential debate drew about 5 million fewer viewers than the network’s previous debate, in September, according to Nielsen Fast National ratings data. While Tuesday’s debate was the third-most-watched primary debate ever — and still drew a sizable audience for CNN — there was a notable falloff in the number of viewers.

The Tuesday debate, moderated by Wolf Blitzer and hosted in Las Vegas, averaged 18 million total viewers, down from September’s CNN Republican Debate that garnered 23 million. Nearly 6 million fewer people watched Tuesday’s debate than watched the first GOP primary debate, hosted by Fox.

In the demo most coveted by advertisers -- people ages 25-54 -- the debate averaged roughly 5.6 million viewers. This ranks third, behind the Fox News Channel debate in August (6.64 million demo viewers) and the first CNN debate, in September (5.98 million).

The showdown featured nine candidates:Billionaire businessman Trump, Sen. Ted Cruz, Marco Rubio, Ben Carson, Jeb Bush, Chris Christie, John Kasich, Carly Fiorina and Rand Paul. The conversation mostly covered national security and the fight against ISIS.

Trump and Jeb Bush engaged in some good old-fashioned mudslinging. "Donald is great at the one-liners, but he's a chaos candidate and he'd be a chaos president," Bush said. "He would not be the commander-in-chief we need to keep our country safe."

Trump promptly fired back, "Jeb doesn't really believe I'm unhinged," he said. "He said that very simply because he has failed in this campaign. It's been a total disaster, nobody cares, and frankly I'm the most solid person up here."

But others were not impressed by some of Trump’s policies that were mentioned, specifically his policy to build a wall around the United States and bar Muslims from entering the country, or track them.

The drop in viewership isn’t sounding alarm bells for CNN, though. Last night’s debate was the second-most-watched program in the network’s history after its September GOP debate. And the audience was bigger than the GOP debates hosted by other cable networks. CNBC on Oct. 28 drew 14 million and Fox Business Network on Nov. 10 drew 13 million.

The next GOP debate is scheduled for January and will air on Fox Business Network. Time will tell if ratings for that event will be, as Trump would say, “yuuge.”