Going into Thursday night's first Republican presidential debate, it seemed as though nothing and no one could stop Donald Trump's rise to the top of the primary field. Insinuate that Mexico is sending rapists to America?  No problem! Question the war hero credentials of Arizona Sen. John McCain?  Poll numbers go up!

But, on the debate stage in Cleveland, Trump faced off with popular Fox News Channel anchor Megyn Kelly -- and it didn't go well for him.  At all.

Here's the full exchange (I left in the "applause" and "laughter" from the official transcript to give you the fullest possible context):

KELLY: Mr. Trump, one of the things people love about you is you speak your mind and you don’t use a politician’s filter. However, that is not without its downsides, in particular, when it comes to women.
You’ve called women you don’t like “fat pigs, dogs, slobs, and disgusting animals.”
Your Twitter account…
TRUMP: Only Rosie O’Donnell.
KELLY: No, it wasn’t.
Your Twitter account…
TRUMP: Thank you.
KELLY: For the record, it was well beyond Rosie O’Donnell.
TRUMP: Yes, I’m sure it was.
KELLY: Your Twitter account has several disparaging comments about women’s looks. You once told a contestant on Celebrity Apprentice it would be a pretty picture to see her on her knees. Does that sound to you like the temperament of a man we should elect as president, and how will you answer the charge from Hillary Clinton, who was likely to be the Democratic nominee, that you are part of the war on women?
TRUMP: I think the big problem this country has is being politically correct.
I’ve been challenged by so many people, and I don’t frankly have time for total political correctness. And to be honest with you, this country doesn’t have time either. This country is in big trouble. We don’t win anymore. We lose to China. We lose to Mexico both in trade and at the border. We lose to everybody.
And frankly, what I say, and oftentimes it’s fun, it’s kidding. We have a good time. What I say is what I say. And honestly Megyn, if you don’t like it, I’m sorry. I’ve been very nice to you, although I could probably maybe not be, based on the way you have treated me. But I wouldn’t do that.
But you know what, we — we need strength, we need energy, we need quickness and we need brain in this country to turn it around. That, I can tell you right now.

So, okay. Trump, backed into a corner by a tough-but-fair question reverted to his standard answer which is: I say things.  You may not like them. I don't care. And then, as he always does, Trump spent the hours after the debate doubling down on his criticism.

He went on to retweet lots of people sending him notes about how great he was and how terrible Kelly was.  In one, he retweeted someone calling Kelly a "bimbo."

It's uniquely possible that, much like the "rapists" and McCain moments, Trump's decision to laugh off disparaging comments he had made about women and then turn his fire onto Kelly might pay off. As I have written many times in the past few weeks, trying to use traditional political logic to assess Trump is a fool's errand.

On the other hand, there's some reason to believe that Trump's I-do-and-say-what-I-want-to-who-I-want schtick may not be enough to get him beyond his comments to and treatment of Kelly.

Kelly, unlike, say, McCain, is immensely popular among conservatives as the face of Fox News Channel. She's likable and positive. It's hard to find someone who has a negative thing to say about her.

Not only that but, again unlike many of Trump's past attackees, Kelly has an hour-long show five nights a week on Fox, the sole news source for many Republicans. Kelly was -- and will continue to  be -- on air A LOT over the coming hours, days and weeks.  And, she was not reticent in the immediate aftermath of the debate to make clear that she felt Trump's response to her was decidedly inadequate.

Kelly is, in short, not one of Trump's usual foes. She has the profile and the platform to make sure her views are heard at least as loudly as his are.

Now, Trump -- up to this point -- has demonstrated a knack for picking fights he can win.  He is a master manipulator of the media and his own image -- oftentimes as the expense of facts.  In picking on Kelly, however, he may have miscalculated.  She might just be the only person out there who can slow Trump's meteoric rise.