Does this blow up Hillary Clinton’s excuses about her secret and unauthorized home-brew e-mail server, or potentially validate them? Fox News’ Catherine Herridge and Pamela Browne report that one of the 29 e-mail chains deemed too classified to release even in redacted form discussed the status of an Afghan national and his ties to the CIA:

One of the classified email chains discovered on Hillary Clinton’s personal unsecured server discussed an Afghan national’s ties to the CIA and a report that he was on the agency’s payroll, a U.S. government official with knowledge of the document told Fox News.

The discussion of a foreign national working with the U.S. government raises security implications – an executive order signed by President Obama said unauthorized disclosures are “presumed to cause damage to the national security.”

The U.S. government official said the Clinton email exchange, which referred to a New York Times report, was among 29 classified emails recently provided to congressional committees with specific clearances to review them. In that batch were 22 “top secret” exchanges deemed too damaging to national security to release.

Sounds damning. Exposing the identities of CIA sources in hostile territory by using unsecure communications channels to discuss them is among the worst kinds of violations in dealing with classified intelligence. This kind of violation would initiate prosecution in most, if not all, instances.

But was this information out in the open? Herridge and Browne note that the references could have been men who had already been outed in the media:

Based on the timing and other details, the email chain likely refers to either anOctober 2009 Times story that identified Afghan national Ahmed Wali Karzai, the half-brother of then-Afghan president Hamid Karzai, as a person who received “regular payments from the Central Intelligence Agency” — or an August 2010 Times story that identified Karzai aide Mohammed Zia Salehi as being on the CIA payroll. Ahmed Wali Karzai was murdered during a 2011 shoot-out, a killing later claimed by the Taliban.

Fox News was told the email chain included then-Secretary of State Clinton and then-special envoy to Afghanistan and Pakistan Richard Holbrooke and possibly others. The basic details of this email exchange were backed up to Fox News by a separate U.S. government source who was not authorized to speak on the record.

This has been Hillary’s defense, in part anyway, in relation to overclassification. If these e-mail chains took place after the newspapers printed these accounts, the argument goes, then the information can no longer do damage to national security because it has already been exposed. Note that this is only applicable if the source discussed was either Karzai or Salehi, and only if the discussion took place after the media reported it openly. Since we will not get a chance to see the e-mails even in redacted form to check classification dates (and the CIA and State aren’t going to confirm identities, obviously), Hillary and her team will insist that this is a case of overclassification.

That argument still does not hold water, however. Even allowing for the most benign circumstances as outlined above, a cardinal rule of handling classified information is that exposure does not automatically declassify it. Discussing these sources over unsecure communications systems still runs the risk of giving enemies confirmation of public reporting and potentially exposing other sources, methods, and information. Only the originating agency could declassify that information. Besides, there is literally no defense for a high-ranking government official whose job relies on intelligence to build a home-brew e-mail system and operate it for official business, where sensitive and classified information can get improperly transmitted and retained, regardless of whether some of it might have gotten exposed in another manner. Ex post facto overclassification complaints are just red herrings.

While we’re mulling over scenarios and circumstances, consider this one: If these e-mails originated before the news reports on these sources, then at least a correlation exists between unsecured communication and eventual exposure. That would make for a much better case if someone chooses to prosecute those involved.