WASHINGTON - Special Counsel Robert Mueller will submit to questions for the first time Wednesday on his explosive report detailing numerous links between President Donald Trump's 2016 campaign and Russian election meddling, and Trump's efforts to obstruct his investigation.

The stakes are high with the next presidential election 16 months away.

With a huge national television audience expected, Democrats want Mueller to help swing public opinion against the president, with some lawmakers hoping he will provide more firepower for an impeachment case against Trump.

But the former FBI director's deep reticence to become embroiled in politics, and Republican plans to turn the hearings into a reality TV-like partisan brawl, threaten to leave Americans no less confused than when Mueller's dense, 448-page report was released in April.

"The public has a right to hear the truth, from Mueller himself, about Trump's misconduct and ongoing national security risks," said Adam Schiff, chair of one of the two House committees hosting Wednesday's marathon testimony.

The final report of Mueller's investigation detailed extensive Russian interference in the 2016 election to boost Trump, and multiple instances of attempted collusion between the campaign and Moscow's agents.

But in the end Mueller, a veteran federal prosecutor, found no crime in that - simple collusion is not a criminal offense, and his team concluded there was not enough evidence to support charges of criminal conspiracy with the Russians.

They also enumerated at least 10 instances where Trump sought to impede the investigation, with strong evidence in support of obstruction of justice allegations.

But Mueller declined to recommend obstruction charges, saying he was blocked from doing so by Department of Justice policy that says a sitting president cannot be charged.

That allowed Trump to declare that he was "exonerated" by Mueller and say the investigation was always a political "witch hunt," claims that have gone far in convincing much of the public that it was much ado about nothing.

"This Witch Hunt must now end. No more Do Overs. No Collusion, No Obstruction. The Great Hoax is dead!" Trump tweeted in early July.

Margaret Taylor, a governance expert at the Brookings Institution think tank in Washington, said the hearings are an opportunity to clarify Mueller's findings.

"I don't think that Americans fully understand the systemic attempts by the Kremlin to interfere, and how the Trump campaign reacted to that," she said in an interview.

"The vast majority of Americans did not read the report," she said.

"I think there is a large portion of the country who hears the president say 'no collusion, no obstruction' and that's the end of the story for them." -AFP