Republican politicians are preparing a media onslaught to deflect, discredit and delegitimise Thursday’s opening hearing of the House of Representatives panel investigating the January 6 insurrection at the US Capitol.

While major TV networks broadcast the first session live in prime time, Rupert Murdoch’s Fox News will stick with its usual show, Tucker Carlson Tonight, which has long pushed Donald Trump’s talking points.

Trump loyalists are expected to flood the airwaves with claims that the January 6 select committee lacks credibility and Democrats are out of touch with more pressing concerns such as inflation, crime, border security and baby formula shortages.

Elise Stefanik, chair of the House Republican Conference, told reporters on Capitol Hill on Wednesday: “They are scrambling to change the headlines, praying that the nation will focus on their partisan witch-hunt instead of our pocketbooks. It will not work.”

In what amounted to an attempt at a prebuttal, Stefanik described the January 6 committee as “unconstitutional” and “illegitimate” and designed to “punish” the House speaker Nancy Pelosi’s opponents. She criticised its decision to hire James Goldston, the former president of ABC News, to help make its presentation compelling.

“This further solidifies what we have known from day one: this committee is not about seeking the truth – it’s a smear campaign against President Donald Trump, against Republican members of Congress, and against Trump voters across this country.”

The comments set the template for Republican counter-programming on conservative media such as Fox News, Newsmax, the One America News Network, Steve Bannon’s “War Room” podcast and other outlets that will seek to portray the hearings as a sinister show trial in which Trump supporters are the victims.

Jim Jordan, the top Republican on the House judiciary committee, wrote on the Federalist website: “The committee’s real goal, and what it hopes to achieve with its unprecedented subpoenas and its bright-light hearings, is a repudiation of conservatism and all those who hold conservative values.”

For their part, Democrats hope that the hearings will cut through a crowded news agenda much more successfully than the former special counsel Robert Mueller’s turgid testimony about Trump’s ties to Russia. After an investigation entailing more than 100 subpoenas, 1,000 interviews and 100,000 documents, they are likely to characterise the riot as not a spontaneous gathering but part of a broader conspiracy.

Congressman Jamie Raskin, a Democrat on the committee, promised in April: “The hearings will tell a story that will really blow the roof off the House. Because it is a story of the most heinous and dastardly political offence ever organised by a president and his followers and his entourage in the history of the United States.”

Trump, whose “big lie” falsely claims that he won the 2020 election, was impeached by the House for his role in encouraging the assault on democracy. Dozens of the insurrectionists have been brought to justice, many having been convicted or pleading guilty to serious crimes.

But Republicans, who previously rejected an independent September 11-style bipartisan commission, have sought to downplay the attack and deny the legitimacy of the committee, alleging that it is driven by political motivations to abolish the electoral college and prevent Trump’s re-election.

They complain that Jordan of Ohio and his colleague Jim Banks of Indiana were barred from taking part by Pelosi. Democrats say the pair were disqualified because they backed Trump’s efforts to overturn the election and sought to block any investigation.

Banks said at a press conference on Wednesday: “Speaker Pelosi blocked us because she’s afraid of what a real investigation would uncover.”

Along with seven Democrats, the committee does have two Republicans but both are staunch Trump critics: Liz Cheney of Wyoming, daughter of the former vice-president Dick Cheney, and Adam Kinzinger of Illinois, who is not seeking re-election. Both were censured by the Republican party in February.

Kinzinger responded to Fox News’s lack of planned coverage by tweeting: “If you work for @FoxNews and want to maintain your credibility as a journalist, now is a good time to speak out, or quit. Enough is enough.”

News coverage of the hearings will be relegated from Fox News to its sister channel, Fox Business Network, which has much lower ratings. Carlson, who will go head to head with the hearing at 8pm on Thursday, has claimed the insurrection “barely rates as a footnote” and described the committee as “wholly illegitimate”.

Tara Setmayer, a former Republican communications director on Capitol Hill turned Trump critic, said: “The Republican party and rightwing media is no longer interested in telling the truth, which is why they’re avoiding showing the hearings.

“Democrats need to consistently hammer home to the American people the importance of what they’re doing and let the facts speak for themselves and not be distracted by the kabuki theatre that Republicans will try to put on to distract from the truth.”

Setmayer added: “The truth is s so damning for the Republican party and they know it. We’re hearing about everything else because they know they can’t stand on the merits of the other side. That’s why we’re hearing about caravans and crime and all of the hot-button cultural issues that fuel the Republican party and get their people riled up instead of the truth of January 6. They can’t handle it.”

Having sought to downplay the deadly insurrection for 17 months, Republicans know the sheer magnitude of Thursday night’s media coverage – aspiring to that of the Watergate hearings that dominated the national conversation in the 1970s – will make it difficult to ignore. It is possible that Trump himself will be stung into speaking out and denouncing the proceedings.

Charlie Sykes, founder and editor-at-large of the Bulwark website and author of How the Right Lost Its Mind, said: “There’s going to be a full-court press to delegitimise the hearings, to throw up as much smoke and dust as possible, which is interesting to me. The conventional wisdom is that these hearings are not likely to move a lot of votes or change the midterm elections but Donald Trump and the Republicans are certainly acting as if they pose a threat. Otherwise, why would they be mobilising like this?

“Obviously they see the hearings as somewhat dangerous. From Trump’s point of view, what he is most concerned about is the fact that it’s going to be on primetime television. He’s a television guy and he understands the power of this and I’m guessing the fact that they’ve hired a guy who’s a documentary maker really got his attention down at Mar-a-Lago.”