Barr last month released a redacted copy of the 448-page report, concluding that neither Trump nor his campaign colluded with Russian Federation to help him win the White House, but reached no conclusion whether Trump, as president, obstructed justice by trying to thwart the prosecutor's 22-month investigation.
"Congress must see the full report and underlying evidence to determine how best to move forward with oversight, legislation and other constitutional responsibilities", Nadler claims - with "other responsibilities" meaning the impeachment that many Democrats expected to launch once Mueller finished up.
"Your refusal to review the less redacted report also hinders our ability to engage in a meaningful discussion about what specific information Congress needs in furtherance of its legitimate legislative activities", Assistant Attorney General Stephen Boyd wrote in a letter to Nadler Monday.
If the panel adopts the resolution, it would then go to the full House for a vote, according to a congressional aide.
A Republican-led House was the first to hold a sitting attorney general in contempt when it acted against Barack Obama's pick Eric Holder in 2012 for failing to turn over documents about a firearms scandal.
He said that if the Justice Department agrees to comply with Nadler's request by providing the full report, he would postpone the vote.
"Each of us believes that the conduct of President Trump described in Special Counsel Robert Mueller's report would... result in multiple felony charges for obstruction of justice", the prosecutors said.
There is some recent precedent for sitting attorneys general to be held in contempt of Congress.
Barr has not given the report to the House and he has refused to appear before the committee.
Brexit deal could be done in ‘next few days’, says Conservative leader
Speaking to reporters afterwards, she said there had been progress in the weeks of talks between the Conservatives and Labour to find a Brexit deal which passes parliamentary muster.
Families of Lion Air crash victims criticise Boeing over alert issue
Boeing also did not flight test what would happen to the MCAS system if the single AOA sensor failed, CNN previously reported . That allowed the airline to activate the sensor-disagree warning lights on its 34 Max jets earlier this year, she said.
Liverpool's Firmino out of Barca visit, Salah at risk
But if we don't do it next Sunday and [Manchester] City are crowned champions, we can be proud of what we've done, everyone. On that note, let's take a look at some wonderful numbers from Liverpool's outing against Newcastle through the slideshow.
White House counsel Pat Cipollone said McGahn does not have any "legal right" to the materials because they are controlled by the White House. Although the report found no evidence of collusion between the Trump campaign and Russian Federation in 2016, Nadler and a cohort of Democrats have pinned their hopes on the unredacted report revealing some evidence of wrongdoing, possibly to kickstart impeachment proceedings against the president.
Attorney General William Barr, who criticized the obstruction probe past year, said after the conclusion of Mueller's investigation that both he and Deputy Attorney General Rod Rosenstein determined Mueller's evidence was "not sufficient" to support prosecuting Trump for obstruction. It also outlined several instances of potential obstruction of justice involving Trump.
Instead of deciding whether to prosecute, Mueller said he would not exonerate Trump and pointed to the Justice Department guidance that a President could not be indicted while in office as a reason for not reaching a conclusion.
It also described attempts by Trump to impede Mueller's probe, but stopped short of declaring Trump committed a crime.
Two days later, Barr sent Congress a four-page letter detailing Mueller's principal conclusion and giving his own finding that there was insufficient evidence to bring obstruction charges against the president.
Trump had previously said he would leave the question to Barr, who has said repeatedly that he has no objection to Mueller testifying.
Nadler said the version of Mueller's report that has already been released to the public offered "disturbing evidence and analysis that President Trump engaged in obstruction of justice at the highest levels".
As the fight with Barr has escalated, Democrats have been in negotiations to hear from Mueller himself.