In the two years since the US Capitol attack, Tucker Carlson has described the violent assault on American democracy connected to the deaths of nine people as “vandalism” and a “forgettably minor” outbreak of “mob violence”.

The Fox News host has said the attack on Congress by supporters of Donald Trump, which has prompted more than 900 arrests, was a “false flag” operation, part of alleged persecution of conservatives by shady government forces. Carlson even devoted much of a conspiracy-laden TV series to undermining the severity of the attack.

It is not difficult to imagine, then, what Carlson might do with the 44,000 hours of Capitol surveillance footage from January 6 handed to him exclusively by Kevin McCarthy, the Republican House speaker. In fact Carlson gave an indication on his show on Monday night.

“Our producers, some of our smartest producers, have been looking at this stuff and trying to figure out what it means and how it contradicts or not the story we’ve been told for more than two years,” Carlson said.

He added: “We think already in some ways that it does contradict that story.”

The January 6 insurrection has proved an obsession for Carlson.

He has devoted countless hours of his nightly show to defending the paticipants, belittling politicians who investigated the attack, and advancing conspiracy theories.

In Patriot Purge, a documentary that ran on the Fox Nation streaming service in November 2021, Carlson led a multipronged attack against the accepted version of what happened on January 6.

Across the three-part series, which attempted to downplay what actually took place while passing off any violence as not the fault of Trump supporters, Carlson dabbled in conspiracy theories and gave a clue as to what we can expect once his producers are done with the Capitol footage.

Carlson used Patriot Purge to claim, without evidence, that the insurrection was actually an FBI-led operation intended to “purge” Trump voters in a “new war on terror”.

He hosted guests who claimed, without evidence, that antifascist activists were seen “changing clothes” into “Trump gear” before the attack began. This claim was overlaid, Media Matters reported, with a clip of a man putting on a sweatshirt. It’s likely Carlson will fish out similar clips over the coming weeks.

The Fox News host has also repeatedly said police were to blame for hundreds of people illegally entering the Capitol.

“Why did authorities open the doors of the Capitol to rioters and let them walk in, usher them in the doors?” Carlson said last year. “That’s utterly bizarre. You saw that live. No one’s ever explained it.”

No one has ever explained it because, according to multiple fact checks, it didn’t happen. Whether that will stop Carlson plucking footage to support the lie remains to be seen.

Whatever happens, it seems unlikely Carlson’s analysis will produce findings similar to those of the bipartisan House committee which investigated the attack.

The committee, which conducted more than a thousand interviews and reviewed much of the footage Carlson has now been given, found that Trump was “was directly responsible for summoning what became a violent mob”, and that the attack was part of an orchestrated “scheme” to overturn the results of the 2020 election.

Fox News did not respond to a request for comment about Carlson’s access to the January 6 footage.

Democrats, as might be expected, responded furiously, a wave of party grandees suggesting McCarthy had made the move to appease the far-right of the Republican party which opposed his bid to be speaker.

As targets of many of the January 6 rioters, Democrats are also worried for their safety in future. Jamie Raskin, the Marylander who served on the January 6 committee, called McCarthy’s move an “ethical collapse”.

“What security precautions were taken to keep this from becoming a roadmap for 2024 insurrection?” Raskin asked on Twitter.

Chuck Schumer, the Senate majority leader, said the footage would “allow those who want to commit another attack to learn how Congress is safeguarded”.

“By handpicking Tucker Carlson, Speaker McCarthy laid bare that this sham is simply about pandering to Maga election deniers, not the truth,” Schumer wrote in a letter to his colleagues.

“If the past is any indication, Tucker Carlson will select only clips that he can use to twist the facts to sow doubt of what happened on January 6 and feed into the propaganda he’s already put on Fox News’ air, which based on recent reports he may not even believe himself.”

That was a reference to a batch of Carlson’s text messages made public as part of a $1.6bn defamation lawsuit against Fox News from Dominion Voting Systems, which appeared to show the host’s private views do not always match what he says on air.

In one text following the 2020 election Carlson described Trump, who he spent hours praising on his show, as a “demonic force” good at “destroying things.

“He’s the undisputed world champion of that,” Carlson wrote. “He could easily destroy us if we play it wrong.”

Other Carlson messages described Sidney Powell, an attorney who claimed Dominion machines flipped votes from Trump to Joe Biden, as “a lunatic”, while conceding “there wasn’t enough fraud to change the outcome” of the election.

In all, it suggests that whatever Carlson and his team now dig out of the January 6 security footage, and whatever Carlson claims that footage shows, will be worth taking with a generous pinch of salt.