The House select committee investigating the January 6 Capitol attack intends to outline at its third hearing on Thursday how Donald Trump corruptly pressured then vice-president Mike Pence to reject the congressional certification of Joe Biden’s win in the 2020 presidential election and directly contributed to the insurrection.

The panel will first examine the genesis of Trump’s pressure campaign on Pence to adopt an unconstitutional and unlawful plan to reject certified electors from certain states at the congressional certification in an attempt to give Trump a second presidential term.

The select committee then intends to show how that theory – advanced by external Trump legal adviser John Eastman – was rejected by Pence, his lawyers and the White House counsel’s office, who universally told the former president that the entire scheme was unlawful.

But Trump deliberately ignored his top White House advisers to go down that path, the panel will show. And, the panel contends, in escalating his campaign to obstruct Biden’s certification through the morning of 6 January 2021, Trump contributed to the violence of the Capitol attack.

The select committee will additionally show that Trump’s false public remarks about Pence having the power to refuse to count votes for Biden – Pence had no such power – directly put the vice-president’s life in danger as the mob chanted “hang Mike Pence”.

Trump’s involvement in the Pence strategy makes the former president liable for the crimes of obstructing an official proceeding and conspiring to defraud the United States, the panel has argued. A federal judge has agreed, calling it “a coup in search of a legal theory”.

The select committee previewed details on the third hearing on a call with reporters. The panel said the hearing would be led by congressman Pete Aguilar, with witness questioning done by former US attorney John Wood, who was appointed senior investigative counsel by vice-chairperson Liz Cheney.

The select committee will hear from Pence’s former counsel Greg Jacob as well as retired former US appellate court judge J Michael Luttig over the course of the hearing, which is expected to last around two hours, according to a source familiar with its planning.

The select committee is likely to focus heavily on the role played by Eastman, who as early as 18 November 2020 was writing memos under the guise of the “Trump legal team” and proposing a brazen plan to send Trump slates of electors to Congress for certification.

But Eastman’s plan to have Pence see that there were “duelling” slates of electors and therefore refuse to certify either Biden or Trump slates – which would result in Trump’s receiving more electoral college votes – relied on states certifying the Trump slates.

On 13 December 2020, the so-called Trump legal team was circulating a “President of the Senate” strategy that referred to Pence taking such action on 6 January 2021, a clear violation of the law governing the certification, according to emails released in court filings.

Crucially, however, the state legislatures had still not met by that date to certify an alternate Trump slate of electors, which Eastman showed in emails that he knew needed to happen in order for his delicate scheme to have any chance of success.

Eastman also undermined the scheme when he admitted in emails on 19 December 2020, released in court filings, that “unless those electors get a certification from their State Legislators”, the Trump slates would be “dead on arrival in Congress”.

The emails showed Eastman knew the plan rested on states certifying Trump slates. But when he presented a memo to Pence in January 2021 attesting to the existence of Trump slates – that did not actually exist – he revealed corrupt intent to obstruct proceedings on 6 January 2021, the panel believes.

No state legislatures ultimately certified an alternate slate of electors for Trump. The Trump White House appears to have participated in a related scheme to send fake Trump slates to Congress, though those were not introduced at the certification on the day of the attack.

But the select committee intends to reveal at the hearing that Pence’s counsel, Jacob, and others including Luttig, all informed the then-vice-president that even if the states had transmitted alternate slates of electors, the plan was unlawful from the start.

The Trump White House counsel separately told Trump that Eastman’s plan violated the law, Cassidy Hutchinson, a top former aide to White House chief of staff Mark Meadows, has also testified to the panel.

Yet Trump and Eastman proceeded with the plan anyway. At the Save America rally on 6 January 2021, Trump told his supporters that he hoped Pence would do the “right thing” and just refuse to certify Biden’s election win, knowing full well by then that it was unlawful.

The select committee is likely to show, finally, that Eastman himself knew the strategy was unlawful. In an email he sent to Jacob as the Trump mob stormed the Capitol, he admitted the scheme violated the law, but then he said Pence could surely violate the law a little more.

Eastman said in the email that because Biden’s certification had been temporarily interrupted by the Capitol attack, Congress had violated the law governing the process. So Pence should have no problem committing “one more minor violation and adjourn for 10 days”, he said.