The three had been called as part of an "aggressive series of hearings" called by Nadler to investigate portions of special counsel Robert Mueller's report into Russian interference in the 2016 presidential election and possible charges of obstruction of justice by Trump.
Nadler, in a written statement, called the White House move “a shocking and dangerous assertion.”
“The President would have us believe that he can willfully engage in criminal activity and prevent witnesses from testifying before Congress — even if they did not actually work for him or his administration.”
Lewandowski was mentioned in the Mueller report, which said Trump asked him twice to ask Attorney General Jeff Sessions to limit Mueller’s investigation.
According to the report, Trump said that if Sessions would not meet with Lewandowski, then Lewandowski should tell Sessions he was fired.
Lewandowski did not ask Sessions to limit Mueller’s investigation, according to the report, but he did pass Trump’s directive off to Dearborn. Dearborn, who had worked as Sessions’ chief of staff when he was a senator from Alabama, was also uncomfortable telling Sessions to tell Mueller to limit the investigation and he, also declined to deliver the message.
Porter who was a staff secretary in the White House, was cited in Mueller’s report which mentioned Porter has taken contemporaneous notes during certain events involving Trump and Sessions.
In the report, Porter told investigators that Trump asked him to “keep in touch with” Justice Department Rachel Brand, suggesting that she could become attorney general. Brand was the third in charge at the Justice Department.
Porter said that he believed that meant that Trump would fire Sessions and Rod Rosenstein, who was the deputy attorney general, the No. 2 position at the Justice Department. Rosenstein appointed Mueller after Sessions recused himself from the investigation of Russian interference in the 2016 presidential election.
“In asking him to reach out to Brand, Porter understood the president to want to find someone to end the Russia investigation or fire the special counsel, although the president never said so explicitly,” Mueller’s investigators wrote. “Porter did not contact Brand because he was sensitive to the implications of that action and did not want to be involved in a chain of events associated with an effort to end the investigation or fire the special counsel.”