“This case is not about what happened on January 6,” assistant US attorney Amanda Vaughan said in her opening statement on Wednesday. “This case is about the defendant thumbing his nose at the orderly processes of our government.”

To make their case, the Justice Department called upon Kristin Amerling, deputy staff director and general counsel for the January 6 committee.

Ms Amerling detailed how Mr Bannon did not comply with the committee’s requests, despite numerous letters sent to his attorneys in October ahead of a 14 October deadline to testify, offering chances to explain his reservations or voice questions or confusion about the process.

She described how Mr Bannon’s attorneys responded that he wouldn’t testify unless the committee reached an agreement with Donald Trump over privilege claims, or if the Trump ally was ordered to testify by a court.

“The select committee’s position was this was not a valid rationale for refusing to comply,” Ms Amerling testified.

After missing deadlines to submit documents to the committee and then sit for a deposition, Mr Bannon’s attorneys eventually argued that an October lawsuit from Donald Trump challenging the January 6 committee’s requests for White House documents should postpone the subpoena.

Ms Amerling testified that the committee found the lawsuit, which was eventually shot down in the Supreme Court this January, to have an “immaterial relationship” over whether Mr Bannon could evade the probe’s requests.

Earlier this month, prosecutors said they had interviewed Trump lawyer Justin Clark, who said the former president had never actually invoked executive privilege over certain materials concerning Mr Bannon in the first place, though in July Mr Trump also sent a letter to Mr Bannon “releasing” him from executive privilege claims.

In court on Wednesday, prosecutors added that regardless of the arguments Mr Bannon was making, many of the materials being sought by the committee weren’t privileged and didn’t involve the president. The materials, they said, include Mr Bannon’s conversations with private parties, members of Congress, and podcast hosts, among other things.

Ms Amerling testified that even though the Supreme Court settled parts of the privilege question in January, the probe didn’t get any indication from Mr Bannon that he might testify until a “sudden” last-minute offer before the impending trial this summer.

The second witness of the day was an FBI agent, Stephen Hart, who reviewed Mr Bannon’s social media posts about the committee subpoena and sat in on a November meeting between the Trump ally’s lawyers and the DOJ about the potential of a criminal contempt case.

Mr Hart showed jurors a post on the social media site Gettr, where Mr Bannon said, “I stand with Trump and the Constitution,” in a Daily Mail article the Trump ally posted on Gettr in October.

Another post shown to the jury saw Mr Bannon say he “will NOT comply” with the committee subpoena shortly after his deadline to respond passed.

The FBI agent also said that in the November meeting, Mr Bannon’s legal team didn’t voice any claims that they had been confused about the deadlines of the subpoena.

Mr Bannon’s defence appeared to be trying to paint the subpoena conversation and resulting contempt of Congress recommendation as a partisan process.

Attorney Evan Corcoran grilled Ms Amerling, the committee counsel, repeatedly about how the subpoena deadlines were set.

“What human set that deadline?” he asked.

She eventually responded that senior committee staff discussed the dates, a decision signed off on by committee chairman Bennie Thompson.

The defence also pressed Ms Amerling about her membership in the same Washington book club as prosecutor Molly Gaston.

“Do you ever discuss the political topics of the day?” he asked.

The committee official said she hadn’t crossed paths with Ms Gaston there in years, and rarely attended meetings.

Additionally, Mr Bannon’s team took issue with FBI agent Hart’s presence at the November meeting between prosecutors and the Bannon team.

"Did you interview for purposes of this case the 200 plus members of Congress who voted not to refer Steve Bannon to the US attorney’s office for contempt of Congress?" they asked the FBI agent.

By the time proceedings were done on Wednesday, the prosecution had rested its case.

Ms Amerling said that the committee was open to further testimony from Mr Bannon, but that his denial of the subpoena was still in violation of the official process.

“We always welcome relevant documents and testimony,” she said.

Court will be back in session on Thursday at 10.30am ET.