Hillary Clinton was rolling along during a CNN-sponsored town hall on Monday night in Iowa. She was forceful and aggressive. Then moderator Chris Cuomo asked her about her email controversy.

Here's the back and forth:

CUOMO: [The Des Moines Register] did question your judgment, though, when it came to the email issue.  They said, and you know this, but for the audience, in 2008 "when she says" — "when she makes a mistake, she should just say so."  This weekend they said that’s a lesson that you have not learned. Yes, you apologized, but only when you needed to, not when you first could have. Fair criticism?
CLINTON: Well, I think that they’re — you know, look, I was delighted to get the Register’s endorsement. And it was a very generous one. And, yes, I think that’s a fair criticism.
You know I had no intention of doing anything other than having a convenient way of communicating, and it turned out not to be so convenient.  So again, we’ve answered every question and we will continue to do so. 
But you know — maybe being faster, trying to scramble around to find out what all of this means, I probably should have done that quicker. 
CUOMO: You’re willing to say it was an error in judgment,  you should’ve apologized…
CLINTON: No. I’m not willing to say it was an error in judgment because what — nothing that I did was wrong.  It was not — it was not in any way prohibited.  And so…
CUOMO: Not apologizing sooner I mean.
CLINTON: Well, apologizing sooner, as soon as you can. But part of the problem, and I would just say this as, not an excuse but just as an explanation. When you’re facing something like that, you got to get the facts. And it takes time to get the facts. And so when I said, hey, take all my emails, make them public. That had never been done before, ever, by anybody. And so we’ve been sorting our way through this because it is kind of a unique situation.  
I’m happy people are looking at the emails. Some of them are you know, frankly, a little embarrassing…
You know. You find out that sometimes I’m not the best on technology and things like that. But, look, I think it’s great. Let people sort them through. And as we have seen, there is a lot of — you know, a lot of interest. But it’s something that took time to get done. 
CNN host Chris Cuomo pushed Hillary Clinton on the email server she used during her time as Secretary of State during the Jan. 25 town hall in Des Moines, Iowa. (CNN)

Not the best. Or even close.

What's clear from her answer is a) Clinton continues to believe that this issue is such a non-issue that it doesn't even deserve a response and b) maybe because of that belief, she continues to not have a concise response to questions that the email story raises about Americans' trust and confidence in her.

Remember that it took Clinton months and months (and months) to acknowledge the obvious — that she needed to apologize for the whole situation (even if she, in her heart of hearts, believed she had nothing to apologize for). She eventually did just that in an interview with ABC's David Muir in September; the next few months, whether by coincidence or because of that apology, were the best of her campaign.

But it's clear from Clinton's response to Cuomo's prodding on Monday night that she simply doesn't really understand why the issue is still a problem for her — in the primary fight against Sanders and/or the general election race. When asked whether she should have apologized sooner, Clinton responded: "I had no intention of doing anything other than having a convenient way of communicating, and it turned out not to be so convenient. So again, we’ve answered every question and we will continue to do so."

Then she went to her too-legalistic-sounding pat response of the months before the apology — and, in so doing, might have made things worse from a political perspective. "I’m not willing to say it was an error in judgment because what — nothing that I did was wrong," Clinton told Cuomo. "It was not — it was not in any way prohibited."

That, of course, is a legal point, not a political one. Clinton continues to not grasp the difference. Legal arguments work in a court of law. This campaign is being fought in the court of public opinion. The same rules simply don't apply.

Imagine this: A TV ad featuring video of Clinton's insistence that "nothing I did was wrong" overlaid with news reports about the number of classified and top-secret messages found on her private server. Now, that might not prove that Clinton was incorrect when she said that she never sent or received any emails marked classified at the time. But, man oh man, does it help drive the narrative that she bent the rules —because, well, she could.

It is, of course, possible that sometime soon the FBI investigation, of which Clinton is not reportedly a target, will turn out to be a giant nothing-burger — a move that would significantly defuse the energy around the issue. (Conservative Republicans would almost certainly still believe that she had done something wrong, but the issue would probably lose salience for the ideological middle of the country.)

As long as there is uncertainty surrounding that investigation, however, Clinton's inability to develop an effective two- or three-sentence response to questions about her emails will haunt her — and provide fodder for Republicans in the general election.