That is the investigation that Sessions promised to stay away from. Firing the man heading the investigation — especially if Sessions knew that the reason was not the one stated in Deputy Attorney General Rod J. Rosenstein’s May 9 memo — is a matter “arising from the campaigns for President of the United States.”

Refusing to recuse oneself from a conflict or breaking the promise to recuse from a conflict is a serious breach of legal ethics. “Someone could file a bar complaint, and/or one with DOJ’s office of professional responsibility, if Sessions had a conflict of interest when it came to the firing decision, and if he did not follow the ethics rules, including those of DOJ by acting when he had a conflict of interest,” legal ethics expert Norman Eisen tells me. “The fact that he broke his recusal commitment, if he did, would be relevant context, and violating an agreement can sometimes in itself be an ethics violation.” In sum, Sessions has risked his law license, whether he realized it or not. He needs to testify immediately under oath; if there is no satisfactory explanation, he must resign. The alternative could be impeachment proceedings.