Donald Trump attempted a coup on 6 January 2021 as he tried to salvage his doomed presidency, and that will be a central focus of forthcoming public hearings of the special House panel investigating events surrounding the insurrection at the US Capitol, the congressman Jamie Raskin has said.

Raskin is a prominent Democrat on the committee and also led the House efforts when Trump was impeached for a historic second time, in 2021, accused of inciting the storming of the US Capitol by his extremist supporters who were trying to stop the certification of Joe Biden’s victory.

“This was a coup organized by the president against the vice-president and against the Congress in order to overturn the 2020 presidential election,” Raskin said in an interview with the Guardian, Reuters news agency and the Climate One radio program.

Public hearings by the bipartisan special committee investigating January 6 and related actions by Trump and his White House team and other allies, chaired by the Mississippi Democrat Bennie Thompson, are expected next month.

“We’re going to tell the whole story of everything that happened. There was a violent insurrection and an attempted coup and we were saved by Mike Pence’s refusal to go along with that plan,” said Raskin.

He was referring to Trump’s vice-president, who went ahead in his role of overseeing the certification of Biden’s win, which was delayed until the early hours of the following day after Pence and other lawmakers, staff and journalists ended up running for their lives as rioters stormed the building, shortly after Trump held a rally near the White House exhorting his supporters to “fight like hell”.

The November 2020 presidential election was deemed by experts at the local, state and federal level to have been “the most secure” in American history, with Trump’s attorney general Bill Barr also concluding that December that the result was accurate.

Raskin told the Guardian, however, that the panel’s hearings would demonstrate to the American public the actions Trump, and the cohort who went along with his efforts, took to overturn the election result.

If the attack on the Capitol had succeeded in preventing the certification of Biden as the incoming president, Raskin asserted that “Trump was prepared to seize the presidency and likely to invoke the insurrection act and declare martial law”.

The insurrection resulted in death and injury to law enforcement and Raskin said that in addition to Pence’s stance against Trump’s demands, the democratic process that day was also saved by “the valor and the bravery of our officers who stood strong against the attempt to just overrun the whole process”.

After a broad criminal investigation, about 800 people have been charged with crimes committed in relation to the Capitol attack.

Raskin said: “We don’t have a lot of experience with coups in our own country and we think of a coup as something that takes place against a president.”

However, January 6 was not what is typically regarded as a coup because it did not involve the military or another faction in society attacking the head of the government.

“It’s what the political scientists call a self-coup … It’s a president fearful of defeat, overthrowing the constitutional process,” Raskin said.

The Maryland congressman is also looking at the bigger, interrelated picture of American democracy and the climate crisis.

“We’ve got to save the democracy in order to save the climate and save our species,” he told the Guardian, Reuters and Climate One in the interview, as part of the Covering Climate Now media collaboration.

Extremist groups were part of the insurrection and have been an outsize, renewed influence on political and social division in the US in recent years.

Raskin said: “We’re never going to be able to successfully deal with climate change if we’re spending all our time fighting the Proud Boys and the Oath Keepers and Ku Klux Klan, and the Aryan nations and all of Steve Bannon’s alt-right nonsense.”