FBI Director James Comey said Tuesday that his agency will recommend no charges against Hillary Clinton in her use of a private email server (actually servers, as he told us), but three little words from his scathing news conference will undoubtedly start a conservative media field day: "at the time."

The significance of this phrase is enormous. We've known for months that during her tenure as secretary of state, Clinton sent and received classified information using her private email account. But the presumptive Democratic presidential nominee's defense has always been that such info was not classified at the time — that it was retroactively upgraded to classified status.

Comey blew up that excuse:

Where an email was assessed as possibly containing classified information, the FBI referred that email to any government agency that might be an owner of that information so that agency could make a determination as to whether the email contained classified information at the time it was sent or received, or whether there was reason to classify it now, even if the content had not been classified when it was first sent or received. And that's the process sometimes referred to as up-classifying.
From the group of 30,000 emails returned to the State Department in 2014, 110 emails in 52 email chains have been determined by the owning agency to contain classified information at the time they were sent or received. Eight of those chains contained information that was top secret at the time they were sent; 36 of those chains contained secret information at the time; and eight contained confidential information at the time. That's the lowest level of classification.

Journalists on the right took note right away.

Beyond the media, the Republican super PAC America Rising immediately turned "at the time" into an anti-Clinton attack ad.

The FBI's recommendation of no charges must be a huge relief for Clinton, but her credibility just took a big hit. She has seemed to be trying lately — at least a little — to make overtures to Trump-hating conservatives through media channels they trust. After going almost two years between appearances on Fox News, she has been a guest twice since March, for instance.

The email investigation came up during her first appearance, a half-hour town hall event, and this is how she explained things to moderator Bret Baier:

CLINTON: I will reiterate — because it's a fact — nothing I sent or received was marked classified. Now, what happens when you ask — or when you are asked to make information public — is that it's reviewed and different agencies come in with their opinions. As you know, just recently, Colin Powell's emails were retroactively classified from more than 10 years ago. As he said, that was an absurdity. I could not agree more.
BAIER: So your contention now is the 2,101 emails contained information that shouldn't be classified at any time, they should be — now or then, you're just saying it shouldn't have been classified?
CLINTON: Well, what I'm saying is, it wasn't at the time.

It sounded like a good answer — except, as it turns out, it wasn't true.

Clinton could potentially peel off some conservative voters who don't like Donald Trump, but she probably can't do it by going on Fox News with bogus excuses. And conservative media types who don't like Trump, either — who might be willing to tell their audiences that Clinton is a better option — aren't likely to help her out right now.

The headline for Clinton is good, but the story could be better. A lot better. "At the time" could cost her an opportunity to win some defections from the right.