Fight all the subpoenas, assert all the privilege

What should we make of the president’s new strategy toward congressional investigations, which is essentially to fight everything, file lawsuits to stop subpoenas, and direct all employees and associates to disobey too?

Should former White House Counsel Don McGahn comply with a subpoena for documents he made in preparation to speak with the special counsel? Are they his to produce? Then, as Josh and Ken recorded this episode, the White House announced it was asserting executive privilege over the full Mueller report, just as the House Judiciary Committee was about to hold a vote on whether to recommend the House hold Attorney General William Barr in contempt. Does asserting executive privilege threaten the balance of power between different branches of government?

And if Robert Mueller does testify (though that is quite uncertain), what might Congress ask him? And how much (if at all) might he stray from what he put in writing in the report?