Former White House chief strategist Steve Bannon went into his testimony with the House Intelligence Committee on Tuesday with orders from his former boss not to discuss anything that went on while he served in the administration.

It made for a frustrating day for the members of the committee.

He did reveal one bit of info, according to sources who spoke to Axios:

Regarding the June 2016 Trump Tower meeting between Donald Trump Jr. and several Russians, Bannon discussed that topic with former White House Chief of Staff Reince Priebus, former press secretary Sean Spicer, and  legal spokesman Mark Corallo.

Bannon immediately realized he’d slipped up and disclosed conversations he wasn’t supposed to discuss, because they happened while he was chief strategist in the White House. Throughout the rest of the session, committee members — in particular Republican Trey Gowdy and Democrat Adam Schiff — hammered Bannon over the fact that he’d mentioned those conversations but refused to discuss anything else about his time in the White House.

Bannon’s lawyer, Bill Burck, told the committee in his opening remarks that Bannon wouldn’t answer any questions that relate to his time inside the White House or during the presidential transition. The committee caught him in the slip-up inside the first 90 minutes.

That Trump Tower meeting is of a particular interest to Robert Mueller’s team, because it is probably the closest instance of collusion uncovered in the ongoing investigation, so far.

Also, the misleading statement that was allegedly crafted on Air Force One by Trump is of interest.

Why lie?

During the proceedings, an official walked in and informed the committee of the grand jury subpoena from Mueller’s team.

That caused a pause, as they consulted on how to proceed with their own questioning.

Trey Gowdy, who led the Republican questioning, pressed Bannon hard on his description of Don Junior’s Trump Tower meeting as “treasonous.” Gowdy asked Bannon whether he would consider it treason for somebody close to him to approach Wikileaks’ Julian Assange to get opposition research on Hillary Clinton. Bannon replied that such a scenario would be bad judgment. Then Gowdy produced emails from a Cambridge Analytica employee — the Trump campaign data firm closely affiliated with Bannon — boasting of just such contacts with Assange. Bannon claimed this was the first time he’d seen these emails (though they’ve been in the news.)

That’s when things got ugly, as Bannon decided to go full-on, alt-right warrior, in his attempt to drain the swamp, right there.

Bannon attacked the Republicans running these congressional committees for choosing to investigate the Trump campaign and Russia. He said it was part of an “establishment” plan to try to “nullify” the election result. Gowdy challenged him on that, asking Bannon who is this establishment you refer to who is trying to nullify Trump’s victory? Bannon answered: Paul Ryan and Mitch McConnell. Gowdy countered that Bannon couldn’t have it both ways. Was he also referring to Trump confidant Kevin McCarthy — the leader of the Republican House conference — who is surely part of the same Ryan-McConnell “establishment?”

Good question.

It seems as if Bannon may really be trying to get back on the Trump train. Maybe somebody should point out to him that Trump has partnered with Ryan and McConnell, and has pretty much been absorbed into the swamp.

When asked if he really thought there was no chance that Trump Jr. didn’t take the Russians up to meet his father during the June 2016 meeting, Bannon seemed to suggest he was speculating.

Throughout the hearing, Bannon kept telling committee members: “I really want to answer this question,” and “I really wish I could answer these questions.” That became a sore point with members. They kept asking him why he felt liberated to abandon executive privilege and leak prolifically about the White House to journalists and author Wolff, but wouldn’t talk to Congress.

Another good question. It may be because everyone thought they had the green light to talk to Wolff, and Bannon, seeing himself as the king maker, felt empowered by the attention.

Bannon has said that he will tell Mueller everything he knows, so that could be an interesting reveal.

One last point sources told Axios was that Bannon praised the committee members for their “professionalism and preparedness,” but someone familiar with Bannon said that that was most likely said tongue-in-cheek.

Well, Bannon is known to be a nasty individual, so a bit of snark would be expected, especially after the heated back and forth over Bannon’s non-answers.