The dirt is out there. The Dems want McGahn to come in and on camera say that Trump tried to get him to fire Mueller, he told Trump that would be illegal obstruction, and Trump asked him not to tell anyone he had asked McGahn to do that.
Fact is, the Trump-Barr playbook worked with the ignoramus Trump base. They bought into Barr's fake summary, they bought into Trump's lying afterward about that, and now they need to see a clip of McGahn saying what is in the report so even those morons can understand they have been duped by conman Trump yet again.
The Trump base is incapable of critical thought. They WANT to be lied to so they can justify what they know in their hearts is a fraud. The only chance there is to snap them out of their Trump trance is to have insiders tell then the truth about Trump.