An FBI agent who allegedly quit the bureau over his belief that the Hillary Clinton email investigation was rigged will testify before the House of Representatives, The Hill reported.

The joint investigation between the House Judiciary and the Oversight Committees — led by Republican Reps. Bob Goodlatte of Virginia and Trey Gowdy of South Carolina, respectively — has been a source of consternation for Republicans and Democrats alike.

Conservatives have complained about the slow pace of the examination into how the Clinton email investigation was conducted, noting that only two witnesses have appeared before it.

Democrats, of course, have complained that it exists at all, since anything that distracts from the endless investigation into how President Donald Trump is really a Russian plant is simply frivolous — particularly if it implicates former FBI Director James Comey, former Secretary of State Hillary Clinton or former President Barack Obama in any wrongdoing.

Well, now we’re finally about to see some fireworks. Three top witnesses are going to testify before lawmakers: John Giacalone, who was in charge of the Clinton investigation for the first seven months; Bill Priestap, assistant director of the FBI’s counterintelligence division; and Michael Steinbach, former head of the FBI’s national security division and the man who succeeded Giacalone.

All three are of particular interest, especially since Priestap was the supervisor of FBI agent Peter Strzok, whose anti-Trump text messages have thrown the objectivity of the entire investigation into doubt.

However, the real headliner here may be Giacalone. Shortly after then-FBI Director Comey announced he wouldn’t be pursuing charges against Hillary Clinton for the email server, Fox News pundit Judge Andrew Napolitano wrote a column in which he claimed Giacalone had quit the bureau because he believed the investigation was rigged.

In the Oct. 28, 2016 column, Napolitano claimed at that at the start of the Clinton email investigation, “agents and senior managers gathered in the summer of 2015 to discuss how to proceed. It was obvious to all that a prima-facie case could be made for espionage, theft of government property and obstruction of justice charges. The consensus was to proceed with a formal criminal investigation.” 

“Six months later, the senior FBI agent in charge of that investigation resigned from the case and retired from the FBI because he felt the case was going ‘sideways’; that’s law enforcement jargon for ‘nowhere by design,‘” Napolitano wrote.

“John Giacalone had been the chief of the New York City, Philadelphia and Washington, D.C., field offices of the FBI and, at the time of his ‘sideways’ comment, was the chief of the FBI National Security Branch.”

“The reason for the ‘sideways’ comment must have been Giacalone’s realization that DOJ and FBI senior management had decided that the investigation would not work in tandem with a federal grand jury. That is nearly fatal to any government criminal case. In criminal cases, the FBI and the DOJ cannot issue subpoenas for testimony or for tangible things; only grand juries can,” Napolitano continued.

“Giacalone knew that without a grand jury, the FBI would be toothless, as it would have no subpoena power. He also knew that without a grand jury, the FBI would have a hard time persuading any federal judge to issue search warrants.”

Napolitano speculated there were several possible reasons that the case went “sideways.” One was that Obama feared having to testify if Clinton went to trial (he had sent emails to the private server, after all, meaning he was aware of it). There was also the fact that a Clinton indictment could have led to Trump becoming president, and Obama simply couldn’t countenance that. (Less than two weeks after Napolitano’s column was written, it must be noted, that reason became moot.)

Either way, if the investigation had indeed gone “sideways,” it would need to have done so with approval from the highest levels — certainly James Comey and possibly Barack Obama.

Whether or not Giacalone has any concrete evidence of this or not is another issue entirely. My guess would be no, given that we’re going on two years since Comey’s infamous news conference and we still haven’t heard anything to that effect from Giacalone.

However, of all of the congressional testimonies we’ve seen over the past few years, this could be one of the most underreported. John Giacalone may open up a gigantic can of worms for Comey and Clinton — one that drags them back in the spotlight for reasons significantly less pleasant than their book tours.