There's talk of House Republicans electing Donald Trump as Speaker of the House. It doesn't seem likely that he could get the votes, but everyone seems to assume it would be constitutional. I'm not so sure.
The relevant constitutional provision is in Article I, Section 2:
The House of Representatives shall chuse their Speaker and other Officers; and shall have the sole Power of Impeachment.
This provision doesn't say expressly that the "Speaker" must be a member of the House, which is why people assume Trump could be Speaker. But, one might argue, "Speaker" had a particular reference in the founding era. No doubt it came from the office of Speaker of the British House of Commons, which long predated the founding era, and there may have been similarly named offices in the state legislatures (I haven't looked into that). I also haven't looked into whether any Speaker of the House of Commons (or of any State) had been anyone other than a member of the relevant body. Let's assume, though, that a "Speaker" (identified by that name) in founding-era practice was always a member. Might we then conclude that "Speaker" meant "a member of an assembly chosen to represent (speak for) that assembly"? I concede that the "other Officers" need not be members, as I assume there was a historical practice of non-member officers. But the Constitution's specific reference to a "Speaker" by title suggests an incorporation of the historical understanding of that office.
There's also a broader point about originalism here. I deliberately didn't look into any historical materials or practice on this point. If it turns out that Speakers of the House of Commons or of state legislatures had in the founding era sometimes been non-members, I would wholly disavow the argument. Sometimes, at least, there are originalist answers.
UPDATE: At Volokh Conspiracy, Jonathan Adler collects commentary on both sides of the issue (but as best I can tell on a quick look no one fully answers the historical question I posed).
FURTHER UPDATE: Andrew Hyman points to this post at Law & Liberty by Mike Rappaport on this issue from many years ago, with input from Andrew and Seth Barrett Tillman. I think we're all thinking about it in the same way, even though the answer may not be clear.
Posted at 6:05 AM