Since the news broke on Tuesday that Donald Trump had fired FBI Director James Comey, Harvard Law School’s Laurence Tribe has been arguing that the president’s conduct, in and of itself, is illegal and amounts to impeachable “high crimes and misdemeanors.”

Tribe has been acting as citizen attorney general in the “shadow Cabinet” formed by progressive leaders in response to the Trump Administration and tweeting from the @ShadowingTrump handle. Tribe’s tweets (from @tribelaw) have become their own form of must-see TV for the resistance. I reached him via email this morning, with a clutch of lingering questions we at Slate have had about the past week.

Dahlia Lithwick: Talk a bit about the recusal rules and the attorney general. I’ve been trying to figure out all week what the consequences are if Jeff Sessions promises to recuse on the Russia investigation, then fires the person leading the investigation. These rules have no real enforcement mechanism if they are violated, right?

Laurence Tribe: Because Sessions has already lied under oath to Congress, this little song and dance of recusal/nonrecusal seems to me part of a pattern of obstruction of justice in its own right. Nobody can bring a civil or criminal action against Sessions for trying to have it both ways, but he needs to be held accountable to the people and the law in some way. And the only way I can see, whatever its political prospects, would appear to be impeachment.

In addition, President Trump’s sneaky decision to rope Sessions into the charade by which he initially offered a transparently phony explanation both to the FBI director and to the American people of why he was canning Comey seems to me part of Trump’s own pattern of obstruction, which I’ve argued is an impeachable offense by the president.

You’re started using the term obstruction of justice with regard to the president, and that’s got a very precise legal meaning. At what point does Trump’s conduct last week rise to the level of illegal obstruction?

In my view, we have clearly passed that point, both as a technical matter under 18 USC 1505, 1512, and 1513, and, much more importantly, as a matter of what might be called the “common law” of presidential impeachment, as established principally by the House impeachment and Senate trial of Bill Clinton and by the articles of impeachment of Richard Nixon.

What is the legal/ethical significance of Donald Trump’s Friday tweet threatening Jim Comey about taping his calls? Clearly, it was bad optics. But was it also more?

That’s a clear instance of witness intimidation under 18 USC 1512-13 and obstruction of pending congressional proceedings under 18 USC 1505, given the obvious likelihood that Comey’s testimony about who convened the infamous White House dinner involving himself and the president and who said what to whom at that dinner will be needed and sought by the pertinent congressional committees. It also helps form part of the damning pattern of obstruction of justice of which President Trump has all but convicted himself.

You are now making the case that even absent any clear connection of collusion between the Trump campaign and Russia to throw the election, Trump is complicit in a cover-up, which is itself illegal? Is this a standalone crime from your perspective?

Absolutely. Blowing smoke in the faces of duly constituted federal investigators so as to trip them up and make it harder both for them to uncover the truth and for them to persuade the people that they have done so is a serious abuse of power, regardless of whether that smoke concealed or came from any real fire. That’s why one so often hears it said that the cover-up can be worse than the crime. And that insight was at the base of the remarkably impressive testimony Sally Yates delivered under oath to a subcommittee of the Senate Judiciary Committee recently.

I have been obsessing for months now about the legal force of Trump’s words and tweets. This was a big theme in the travel-ban arguments at the Fourth Circuit last Monday. Are his admissions—say to NBC News, that Comey was fired because of the Russia investigation—of any legal moment? His supporters continue to say these are just words.

Words can be deeds (“performative speech”), as when one pleads guilty to a crime in open court or says “I do” in a formal marriage ceremony—not to suggest that those two are substantively similar!

And even when words are not genuine examples of performative speech—“speech acts,” whose very utterance changes the legal reality—they can operate as “real threats” (as in cases of overt or covert witness intimidation, akin to Trump’s thinly veiled threat to Comey in his now-infamous tweet) and can both shape the impact of the deeds they accompany (as when someone says “I’m excluding you from the country because I think Islam is a violent religion and Muslims suck”) and provide crucial evidence of why those deeds were performed (as when one says “I’m firing you because I think Muslims are dangerous”), which constitutional doctrine often makes decisive, or at least relevant, in assessing the lawfulness of government actions.

The professors’ amicus brief written by Joshua Matz that I joined in the en banc circuit court proceedings involving Trump’s travel ban was a powerful explication of that key principle of constitutional adjudication.

James Clapper is saying that Trump also was not truthful about morale at the FBI under Comey. Is that material? At what point are the steady stream of provable lies from the president relevant to your claims about high crimes and misdemeanors?

Deliberately misleading federal investigators and other federal employees was among the charges included in Article One (obstruction of justice) of the Bill of Impeachment against Nixon.

And deceiving the American public on matters directly pertinent to the institutions and processes of government, taking advantage of one’s high federal office to give one’s lies both cover and credibility, is certainly a grave abuse of executive power—and is indeed the essence of the unenumerated offenses the Framers clearly contemplated by the open-ended phrase, “high crimes and misdemeanors.”

Even if lying to and/or misleading the public—as opposed to deceiving official bodies under oath—is not and could not be made a civil offense, that by no means implies that such a pattern of deliberate deceit is irrelevant to the ultimate inquiry of whether one has forfeited the public trust that alone entitles one to retain a position of power in the United States government.