McGahn, who left his post in October, was told by the Trump administration on Monday to disregard a House Judiciary Committee subpoena demanding that he appear at the hearing to discuss the Russian election meddling investigation.
The Department of Justice issued a legal opinion saying McGahn did not need to appear, and late on Monday, McGahn’s lawyer, William Burck, wrote that his client would not testify before the committee unless the judiciary panel reached an agreement with the White House.
The committee’s Democratic chairman, Jerrold Nadler, made clear the hearing would go ahead regardless.
The White House’s open defiance of the committee follows a pattern of determined stonewalling of numerous congressional inquiries into Trump and his turbulent presidency.
Trump and most fellow Republicans in Congress dismiss the inquiries as political harassment ahead of the 2020 elections.
However, House Republican Justin Amash, a frequent Trump critic and outspoken Michigan conservative, said over the weekend that the president “has engaged in impeachable conduct.”
Counter-punching in his usual style, Trump told reporters late on Monday outside the White House that Amash is “a loser.”
On another front, in a legal setback for Trump, a U.S. judge on Monday ruled against him in a case involving another House panel. The House Oversight Committee has subpoenaed Trump’s financial records from his long-time accounting firm Mazars LLP.
In an unusual move, lawyers for Trump and the Trump Organization, his company, last month sued to try to block the subpoena. U.S. District Judge Amit Mehta in Washington ruled against Trump and denied his request for a stay pending appeal.
As a power struggle has escalated between Trump and Congress over its powers to investigate him, Democrats have raised growing concerns about the president’s conduct, especially since the mid-April release of the Mueller report.
“We simply cannot sit by and allow this president to destroy the rule of law … If Mr. McGahn doesn’t testify tomorrow, I think it is probably appropriate for us to move forward with an impeachment inquiry,” Democratic Representative David Cicilline, a Judiciary Committee member, told MSNBC.
The redacted, 448-page report from Special Counsel Robert Mueller, 22 months in the making, showed how Moscow interfered in the 2016 U.S. presidential election in Trump’s favor and detailed Trump’s attempts to impede Mueller’s probe.
The report found there was insufficient evidence to allege a criminal conspiracy between Moscow and the Trump campaign. It made no recommendation on whether Trump obstructed justice, leaving that question up to Congress.
“The president acted again and again — perhaps criminally — to protect himself from federal law enforcement. Don McGahn personally witnessed the most egregious of these acts…. (Trump) clearly does not want the American people to hear firsthand about his alleged misconduct,” Nadler said in a statement.
“Senior advisers to the president cannot simply refuse to appear in response to a congressional subpoena,” Nadler said.
If McGahn fails to appear he would follow the lead of Attorney General William Barr, who skipped a hearing before House Judiciary Committee on May 2.
The panel later voted to recommend that the full House hold Barr in contempt of Congress for refusing to release an unredacted version of the Mueller report. Nadler has threatened to hold McGahn in contempt if he fails to show up.
Trump earlier this month cited the controversial doctrine of executive privilege to block another Judiciary Committee subpoena seeking an unredacted version of Mueller’s final report.
In the report, McGahn was a key witness regarding possible obstruction of justice by Trump. Career prosecutors who are not involved in the case have said that the report contained strong evidence that Trump committed a crime when he pressured McGahn to fire Mueller and later urged him to lie about the episode.
Reporting by Sarah N. Lynch; Editing by Kevin Drawbaugh and Cynthia Osterman