House Democrats will try to focus US Special Counsel Robert Mueller's testimony on clear examples of conduct by President Donald Trump that would lead to criminal charges against any other American when he appears in Congress on Wednesday.
The strategy, described by Democratic congressional aides at a briefing for reporters, is intended to build support among Americans for an investigative agenda that Democrats plan to advance, possibly leading to impeachment proceedings.
Republicans, who say Mr Trump is the victim of a political attack by Democrats and former Justice Department officials, plan to use Mr Mueller's appearance to explore the origins of his investigation and also the politics of his former team.
Mr Mueller, who for nearly two years dug into Russian meddling in the 2016 US presidential election and Mr Trump's efforts to impede his probe, will appear under subpoena separately before the House of Representatives Judiciary and Intelligence committees.
He is expected to spend about five hours in total delivering testimony that is unlikely to stray from the 448-page report he submitted in April.
The former special counsel did not find sufficient evidence to establish that the Trump campaign conspired with Russia and declined to make a judgment that Mr Trump obstructed justice.
However, his report said: "If we had confidence after a thorough investigation of the facts that the president clearly did not commit obstruction of justice, we would so state."
Democrats contend the report contains shocking descriptions of behaviour by the president that most Americans are unaware of, including alleged efforts by campaign officials to welcome and even capitalise on Russian election interference and then try to cover up their actions.
For Democrats, a goal at the hearing will be to get Mr Mueller to help connect evidence pointing to misconduct into a "meaningful and compelling account" for the public, said the aides, who spoke on condition of anonymity.
House Judiciary Democrats will try to get Mr Mueller to focus on five instances of possible obstruction described in the Mueller report including witness tampering, aides said.
The report said Mr Trump tried to remove Mr Mueller and then cover up his actions; sought to persuade former Attorney General Jeff Sessions to direct the Russia probe away from the campaign; and appeared to dangle pardons before former campaign manager Paul Manafort and personal lawyer Michael Cohen while they faced federal prosecution.
Much of the questioning will centre on former White House Counsel Don McGahn, whom Mr Mueller said Mr Trump directed to remove the special counsel and then to deny he was told to do so.
Mr McGahn refused to carry out Mr Trump's instructions.
Mr Mueller made no determination on whether Mr Trump committed the crime of obstruction in light of a Justice Department ban against indicting sitting presidents.
But the former special counsel also did not exonerate Mr Trump.
Democratic Judiciary Committee aides said lawmakers hope to show that some of the president's actions, which he repeated again and again, would land any other American with a multi-count indictment.
Meanwhile, House Intelligence Committee lawmakers will concentrate on evidence that the Trump campaign allegedly welcomed Russia's election interference, used the assistance, based campaign messaging on it and then tried to cover up their actions by lying to federal investigators, aides said.
Democrats on the panel will also focus on whether Mr Trump knew when he touted WikiLeaks during the campaign that the group possessed emails damaging to his Democratic rival Hillary Clinton that were hacked by Russia, aides said.