One of the main arguments against the impeachment and potential conviction of Donald Trump is that his trial and conviction (if any) will now occur only after he has left office. Critics, most notably prominent former federal Judge Michael Luttig, argue that this is unconstitutional.

Protect Democracy has recently posted a letter signed by over 170 legal scholars, setting forth the reasons why impeachment and trial of officials who have left office is in fact constitutional.

The list of signers is notable for its ideological diversity—unusual in an era when legal scholars' views on controversial issues are often polarized along ideological lines. Notable conservative and libertarian signers include Steve Calabresi (co-founder of the Federalist Society, and leading academic expert on executive power), Michael Stokes Paulsen, and my co-bloggers Jonathan Adler and Sasha Volokh. I myself have signed the letter, as well.

Another VC co-blogger, Keith Whittington, did not sign the letter, but has written an excellent article on Lawfare reaching the same conclusion. Keith is one of the nation's leading right-of-center originalist legal scholars. I myself previously wrote about the issue here.

Signers also include a large number of prominent center and left legal scholars (including Laurence Tribe, Martha Minow, Neil Siegel, and Rebecca Zietlow, among many others), and several prominent experts on impeachment, such as Frank Bowman and Brian Kalt (author of what is the best-known and by far the most thorough academic article on the subject of impeaching former officials).

Here is an excerpt from the letter:

We take no position on whether the Senate should convict President Trump on the article of impeachment soon to be transmitted by the House of Representatives.

We differ from one another in our politics, and we also differ from one another on issues of constitutional interpretation. But despite our differences, our carefully considered views of the law lead all of us to agree that the Constitution permits the impeachment, conviction, and disqualification of former officers, including presidents.

Our shared conclusion is supported by the text and structure of the Constitution, the history of its drafting, and relevant precedent. The Constitution allocates the "sole Power of Impeachment" to the House of Representatives, and the "sole Power to try all Impeachments" to the Senate. It provides that the "President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors." It further specifies that "Judgment inCases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States."

In other words, the Constitution's impeachment power has two aspects. The first is removal from office, which occurs automatically upon the conviction of a current officer. The second is disqualification from holding future office, which occurs in those cases where the Senate deems disqualification appropriate in light of the conduct for which the impeached person was convicted. The impeachment power must be read so as to give full effect to both aspects of this power.

Impeachment is the exclusive constitutional means for removing a president (or other officer) before his or her term expires. But nothing in the provision authorizing impeachment-for-removal limits impeachment to situations where it accomplishes removal from office. Indeed, such a reading would thwart and potentially nullify a vital aspect of the impeachment power: the power of the Senate to impose disqualification from future office as a penalty for conviction.

The fact that the position outlined in the letter is backed by such a wide range of experts doesn't automatically prove it is correct. Experts can be wrong, sometimes even spectacularly so. Nonetheless, for reasons I summarized in 2015 (long before the current impeachment controversy), it often makes sense for laypeople to extend experts a degree of deference when the latter are addressing matters within their areas of specialization, and expert agreement cuts across ideological lines (making it less likely that it is simply the product of ideological or partisan bias).

Even if the other signers and I are right about this specific issue, there are other potential objections to convicting Trump, both legal and pragmatic. The letter doesn't address those questions, though I have tried to do so myself in other writings (e.g. here and here). But the question of the constitutionality of impeaching former presidents has emerged as a major focus of debate, and the scholars' letter will, I expect, be a useful contribution to that discussion.