Donald Trump will “fight even harder” on the road to a possible White House run in 2024 because of the acquittal of a lawyer for Hillary Clinton’s 2016 campaign on a charge of lying to the FBI.

“If anything, it makes me want to fight even harder,” the former president told Fox News Digital. “If we don’t win, our country is ruined. We have bad borders, bad elections and a court system not functioning properly.”

Trump beat Clinton in 2016 but lost to Joe Biden in 2020, a defeat he refuses to accept, claiming it was caused by electoral fraud.

That lie inspired the deadly attack on the US Capitol on 6 January 2021, by supporters Trump told to “fight like hell”. A bipartisan Senate report linked seven deaths to the riot. More than 800 people have been charged, some – members of a far-right militia – with seditious conspiracy. A House select committee will soon hold public hearings.

Trump was impeached for inciting an insurrection but acquitted, leaving him free to run for office. In legal jeopardy over his attempt to overturn the election and his business affairs, he has said he will decide on a run after midterm elections this year.

The strength of Trump’s hold on the Republican party has come under question after primary defeats for candidates he endorsed. But he remains popular with the party base. Democrats and other observers have raised the alarm about Trump loyalists moving to take over crucial elections posts in swing states.

The Clinton lawyer, Michael Sussmann, was charged with lying to the FBI when he pushed information meant to cast suspicions on Trump and links to Russia. He was acquitted on Tuesday.

The case was the first test of the special counsel John Durham since his appointment three years ago to search for misconduct in the investigation into Russia and Trump. Trump supporters have looked to Durham to expose what they say was FBI wrongdoing.

The trial focused on whether Sussmann, a cybersecurity attorney and former federal prosecutor, concealed from the FBI that he was representing Clinton’s campaign when he presented data he said showed a possible backchannel between the Russia-based Alfa Bank and the Trump Organization.

The FBI determined that there was no suspicious contact.

The bureau’s then general counsel, James Baker, testified that he was “100% confident” Sussmann told him he was not representing any client. Prosecutors said Sussmann was actually acting on behalf of the Clinton campaign and another entity.

Sussmann’s lawyers denied that he lied and said that even if he made a false statement it was irrelevant since the FBI was already investigating Russia and Trump.

Trump claims a vast conspiracy. Speaking to Fox News Digital, he said: “They spied on my campaign. They got caught. If a Republican would have done that, and the obvious steps forward, it would be a virtual death penalty.”

He also said: “This was totally illegal. What they did was treason, and it also put our country in a lot of danger with Russia.”

Robert Mueller, the special counsel who investigated Trump and Russia, did not find evidence of direct collusion. He did lay out extensive evidence of contacts between Trump aides and Moscow, and he indicted or received guilty pleas from 34 people and three companies, and detailed 11 incidences of possible obstruction of justice by Trump or his campaign.

Trump asked: “Where do you get your reputation back?”