At the end of last month, with the midterms looming, I gave a talk before a small private audience in California in which I argued for optimism because—among other things—the moment for firing Robert Mueller had passed.

Eighteen months ago, I said, President Donald Trump had an opportunity to disrupt the Russia investigation: He had fired the FBI director and had rocked the Justice Department back on its heels. But Trump had dithered. He had broadcast his intentions too many times. And in the meantime, Mueller had moved decisively, securing important indictments and convictions, and making whatever preparations were necessary for hostile fire. And now Democrats were poised to take the House of Representatives. The window of opportunity was gone.

In the 48 hours since Trump fired Jeff Sessions and installed Matthew Whitaker as acting attorney general, I have had occasion to wonder whether I was being overly optimistic a week ago. Whitaker is the kind of bad dream from which career Justice Department officials wake up at night in cold sweats. He’s openly political.