Attacking the press for unfair coverage has long been a bipartisan pursuit. Sometimes it works. I am happy to say that more often it doesn't. But Trump's brand of vituperation is particularly personal and vicious. It carries with it the drumbeats of threatening violence. It cannot be left unanswered.

This is not about politics or policy. It's about protecting our most cherished principles. The relationship between the press and the powerful they cover is by its very definition confrontational. That is how the Founding Fathers envisioned it, with noble clauses of protection enshrined in our Constitution.

Good journalism — the kind that matters — requires reporters who won't back up, back down, back away or turn around when faced with efforts to intimidate them. It also requires owners and other bosses with guts, who stand by and for their reporters when the heat is on.