Yes, especially considering the by-line of the piece. Eugene Volokh isn't a WaPo reporter. He's the namesake of The Volokh Conspiracy, a blog that WaPo publishes; and also a law professor and leading expert on First Amendment law.

EDIT: Prof. Volokh just posted in his blog a bit about how the piece came to be. See https://www.washingtonpost.com/opinions/donald-trumps-vile-c...