The FBI has made some emails received by Hillary Clinton over a less secure system that dealt with drone strikes in Pakistan a key part of their criminal investigation, according to the Wall Street Journal.

Occasionally, diplomats in Pakistan and Afghanistan would send the State Department emails over a non-secure server in order to expedite a decision on whether to go ahead with a proposed drone strike.  Clinton or one of her aides would then forward the email using her private, unsecured server. 

The 2011 and 2012 emails were sent via the “low side’’—government slang for a computer system for unclassified matters—as part of a secret arrangement that gave the State Department more of a voice in whether a Central Intelligence Agency drone strike went ahead, according to congressional and law-enforcement officials briefed on the Federal Bureau of Investigation probe.

Some of the emails were then forwarded by Mrs. Clinton’s aides to her personal email account, which routed them to a server she kept at her home in suburban New York when she was secretary of state, the officials said. Investigators have raised concerns that Mrs. Clinton’s personal server was less secure than State Department systems.

The vaguely worded messages didn’t mention the “CIA,” “drones” or details about the militant targets, officials said.

The still-secret emails are a key part of the FBI investigation that has long dogged Mrs. Clinton’s campaign, these officials said.

They were written within the often-narrow time frame in which State Department officials had to decide whether or not to object to drone strikes before the CIA pulled the trigger, the officials said.

Law-enforcement and intelligence officials said State Department deliberations about the covert CIA drone program should have been conducted over a more secure government computer system designed to handle classified information.

State Department officials told FBI investigators they communicated via the less-secure system on a few instances, according to congressional and law-enforcement officials. It happened when decisions about imminent strikes had to be relayed fast and the U.S. diplomats in Pakistan or Washington didn’t have ready access to a more-secure system, either because it was night or they were traveling.

Emails sent over the low side sometimes were informal discussions that occurred in addition to more-formal notifications through secure communications, the officials said.

It appears that both the State Department and Clinton violated security protocols, with the difference being Clinton's private server being more susceptible to hacking.  By definition, the emails weren't "classified," although that might be a distinction without a difference.  If they contained classified information, no matter what it said in the header, Clinton is guilty of mishandling sensitive information.

From what we've seen of the investigation, it appears that Clinton aides Huma Abedin and Cheryl Mills are going down after they forwarded dozens of classified emails over Hillary's server.  Will Clinton join them?  Even though I'm a betting man, I'm not going to give any odds on that.