I think probably, you know, from my perspective, the folks who say a sitting president cannot be indicted have the better of the argument that the president can't be indicted - put, you know, through a criminal trial while he is president - and that the proper way to do it is to impeach him first, remove him, and then seek criminal prosecution.
I've been in two different administrations, and I would say, particularly, President Obama was really careful to make sure that he wouldn't invoke executive privilege unless absolutely necessary. He only invoked it once in eight years, even though many years he had Congress opposed to him in terms of being from the opposite party.
President Trump has criticized the Mueller investigation, fired Jim Comey, savagely attacked the FBI, and repeatedly suggested the Russia campaign influence in 2016 was a hoax. In the wake of all of this, the American people need to be assured that Mueller can carry out his investigation without interference.
Some commentators have attacked the special counsel regulations as giving the attorney general the power to close a case against the president, as Mr. Barr did with the obstruction of justice investigation into Donald Trump. But the critics' complaint here is not with the regulations but with the Constitution itself.