House Judiciary Committee Chairman Jerry Nadler (D-NY) slammed Trump over on potential instances of obstruction of justice outlined in special counsel Robert Mueller's report.

"I believe that each of these incidents documented in detail in the Mueller report constitutes a crime," Nadler said. "But for the Department of Justice's policy of refusing to indict any sitting president, I believe the president would have been indicted and charged with these crimes" he continued after reading aloud the instances of potential obstruction of justice outlined in the report.

Nadler also had some strong words for former White House Counsel Don McGahn who refused to appear, citing Trump's instruction that he not testify to the Democrat-led House Judiciary Committee.

"Let me be clear: this committee will hear Mr. McGahn's testimony, even if we have to go to court to secure it," Nadler said at the outset of the hearing.

"We will hold this president accountable, one way or the other," Nadler said.

On Monday, the White House informed the committee that McGahn would not be showing up for the hearing but Nadler argued that the White House is invoking executive privilege to conceal evidence of wrongdoing or criminality. 

"Yet as I have already made clear, the Committee plans to ask you about instances in which the President took actions or ordered you to take actions that may constitute criminal offenses, including obstruction of justice," Nadler wrote in a letter to McGahn.

"Despite the [Justice] Department's apparent efforts to catalogue every instance in which a White House aide has refused to testify before Congress, the Department can cite no example where Congress planned to ask that White House aide about possible crimes committed by the President. Perhaps that is because – until now – no President would have engaged in such a transparent effort to block his own former aides from testifying about the President's misconduct."

What are they hiding?