It was a very Donald Trump moment.

In the final stretch of the first general-election debate, the Republican presidential nominee basically stopped the ordinary flow of questions and answers to say this, apropos of almost nothing. Democratic rival Hillary Clinton had just outlined an accurate list of names Trump has called various women in public. Trump's response came in an exchange with the moderator, NBC News anchor Lester Holt:

TRUMP: You know, Hillary is hitting me with tremendous commercials. Some of it's said in entertainment. Some of it's said — somebody who's been very vicious to me, Rosie O'Donnell, I said very tough things to her, and I think everybody would agree that she deserves it and nobody feels sorry for her.
But you want to know the truth? I was going to say something ...
HOLT: Please, very quickly.
TRUMP: ... extremely rough to Hillary, to her family, and I said to myself, "I can't do it. I just can't do it. It's inappropriate. It's not nice." But she spent hundreds of millions of dollars on negative ads on me, many of which are absolutely untrue. They're untrue. And they're misrepresentations.
And I will tell you this, Lester: It's not nice. And I don't deserve that.
But it's certainly not a nice thing that she's done. It's hundreds of millions of ads. And the only gratifying thing is, I saw the polls come in today, and with all of that money ...

That was, effectively, a very Trump way of not saying something and at the same time hinting so strongly at just what he said he would not say, that only inanimate objects and amoeba failed to understand what he was not saying. Of course, the "extremely rough" thing Trump stopped himself from saying "to Hillary, to her family" was most likely about Bill Clinton's history of marital infidelity, the Clinton's public decision to stay together, and/or what he regards as Hillary Clinton's role in criticizing and discrediting women who over the years have told reporters they had some sort of sexual contact with Bill Clinton.

How do we know? Well, consider what Trump said to Fox News Channel host Sean Hannity in an interview almost immediately after Monday night's debate:

HANNITY: Last point, at the end of the debate, maybe a sign of desperation, she tried to attack you as sexist. What is your response to that?
TRUMP: Well I didn’t want to say that her husband was in the room along with her daughter, who I think is a very nice young lady. And I didn’t want to say what I was going to say about what’s been going on in their life. So I decided not to say it. I thought it would be very disrespectful to Chelsea and maybe to the family. But she said very bad things about me. I mean worse than what she’s said. She’s taking these phony ads, spending hundreds and millions of dollars on phony ads. And I think that it’s a disgrace that she’s allowed to do that.

Then there was the interview that Trump gave CNN's Dana Bash after the debate in which he mentioned Bill Clinton's "indiscretions" directly and said he may not be done with the subject of the Clinton marriage yet. From CNN:

Trump told CNN's Dana Bash Monday that he might bring up former president Bill Clinton's past marital indiscretions at the next debate.
"I'm very happy that I was able to hold back on the — you know, on the indiscretions with respect to Bill Clinton, because I have a lot of respect for Chelsea Clinton and I just didn't want to say what I was going to say," he said.
"Which is?" Bash asked.
"Which is, I'll tell you maybe at the next debate. We'll see," Trump replied.

So it seems that the twice-divorced, thrice-married Trump — who leaked information about an affair he had during his first marriage to New York newspapers — has put Clinton and her camp on notice. Well, first, he congratulated himself for what he described as his discretion and restraint. Then he made at least three public hints that he's thinking about Bill Clinton's infidelities.

If and when Trump decides to unleash his thoughts on the Clinton marriage in an overt way, Clinton's campaign has said she is ready.

Things have already gotten ugly. They could get uglier still.