The committee is investigating the administration's policy of separating migrant children from their parents at the U.S. -Mexico border. Republicans, meanwhile made their complaints loudly known at a Thursday hearing to vote on subpoenas, repeatedly criticizing House Judiciary Chairman Jerry Nadler for agreeing to limit the length of the hearing in order to get Mueller to testify.
New York Rep. Hakeem Jeffries, a member of the panel, said before the meeting that he expects to discuss "what the team strategy is going to be as we begin an intensive phase of preparation". He said the witnesses "have already spent hours with Robert Mueller, and spent a fortune on lawyers in so doing".
The House Judiciary Committee authorized subpoenas Thursday to a number of key officials from Trump's orbit as part of its investigation into possible obstruction of justice, corruption and abuse of power: former Attorney General Jeff Sessions, former Deputy Attorney General Rod Rosenstein, former Trump Chief of Staff John Kelly and former Trump campaign manager Cory Lewandowski.
That includes a return to the Iran nuclear deal - adopted under Obama in 2015 and abandoned by President Trump past year - renewed support for North Atlantic Treaty Organisation and additional focus on an Obama-era program that traded aid for Central American leaders' commitments to tamp down various crises that are sending migrants streaming to America's doorstep.
David Pecker, a longtime Trump friend and publisher of the tabloid National Enquirer, will also be summoned to testify before the committee.
"We got rolled", said Georgia Rep. Doug Collins, the top Republican on the Judiciary panel.
"I believe that we must meet our obligation to protect and defend the American people and our constitution".
The stern, reticent former Federal Bureau of Investigation director has said he won't answer questions beyond what is in the report on Russia's election meddling and the Trump campaign and possible obstruction of justice when he comes to Congress on July 17.
Rep. Andy Biggs, Arizona Republican, says he'll ask Mr. Mueller when it became clear to them that Mr. Trump "was no longer the core focus of an investigation", a way of underscoring the conclusion that he didn't conspire.
And it comes less than a week before Mueller testifies before the committee about his report, a televised event that Democrats hope will better inform the public about the details in the 448-page document that is thick with legal analysis. He also accused Democrats of wasting time.
Republicans, meanwhile, say viewers will finally get to hear Mr. Mueller put a nail in conspiracy theories that the Trump campaign conspired with Russian Federation to steal the 2016 election.
Mueller said at a May news conference that charging a president with a crime was "not an option" because of longstanding Justice Department policy. Arizona Rep. Debbie Lesko, a junior Republican on the panel, said the decision to exclude some members from questioning is "just plain wrong".